Description:A METHOD, APPARATUS, AND SYSTEM FOR A NOVEL BROADBAND SELF-POWERED ANTIMONY TELLURIDE (Sb2Te3) AND MOLYBDENUM DITELLURIDE (MoTE2) HETEROSTRUCTURE PHOTODETECTOR FOR INFRARED DETECTION

Technical Field:

[001] Embodiments disclosed in the present application relates to a novel photodetector (or photodiode) device and specifically to a method, apparatus, and systems for a novel broadband self-powered antimony telluride (Sb2Te3) and molybdenum ditelluride (MoTe2) heterostructure photodetector for infrared detection.

Background:
[002] Photodetectors (or photodiodes) play an important role in a vast range of applications such as light detection and ranging (LiDAR), medical applications, optical fiber communication, imaging systems (including night vision, thermal imaging), environmental sensing (e.g., gas detection, remote sensing), bioluminescence, absorbance, dark matter detection, detection of oil logging, rock density, porosity and chemical composition detection, for example. Current photodetectors such as such as Indium Gallium Arsenide (InGaAs) or Mercury Cadmium Telluride (HgCdTe) devices, often have one or more limitations including high fabrication costs, the need for cryogenic cooling, or a limited spectral response range. Additionally, current devices require continuous external bias, increasing both power consumption and system complexity.

Summary:
[003] Embodiments of a method, apparatus, and systems for a novel broadband self-powered antimony telluride (Sb2Te3) and molybdenum ditelluride (MoTe2) heterostructure photodetector for infrared detection. In one embodiment, a novel Sb2Te3/ MoTe2 may heterostructure photodetector provide:
[004] (a) a self-powered photodetector employing a Sb2Te3/MoTe2 heterostructure may be capable of broadband detection extending into the infrared region (up to ~2500 nm).
[005] (b) By leveraging the properties of Sb2Te3, combined with a transition metal dichalcogenide (MoTe2) layer, an improved carrier separation and reduced recombination may be achieved without the need for external bias.
[006] (c) Structurally, the novel photodetector may, in one embodiment, may include a Si/SiO2 substrate, a thin layer of MoTe2 grown on top of the Si/SiO2 substrate, and atop MoTe2 thin film, a sputtered Sb2Te3 layer (~200 nm) may be deposited, with Ti/Pt contacts on both the thin layer of MoTe2 and sputtered Sb2Te3 layer
[007] (d) the interface surface of thin layer of MoTe2 and sputtered Sb2Te3 layer may form a heterojunction that may generate a built-in electric field. The built-in electric field may drive photocurrent under illumination thus enabling self-powered operation.
[008] In one embodiment, the integration of Sb2Te3 and MoTe2 films into a stacked heterostructure may enable broad spectral response in visible to IR band and high responsivity under zero bias. The detection in the infrared range may extend up to (2500nm, approximately) and the dark current may be reduced to (10nA) and the photo-response time may decrease to 6ms enabling the photodetector to perform the sensing efficiently and quickly.
[009] In one embodiment, the sputtering-based fabrication of such photodetectors may be scalable, making it suitable, for example, for applications in imaging, environmental monitoring, optical communications, and security.

Brief description of Drawings:
[0010] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate embodiments of the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art(s) to make and use the invention. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number.
[0011] The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, algorithm, and other changes. Portions and features of some embodiments may be included in, or substituted for, those of other embodiments. Embodiments set forth in the claims encompass all available equivalents of those claims.
[0012] FIG. 1 illustrates a photoemitter 110 and a photodetector 120 combination according to an embodiment.
[0013] FIG 2 illustrates a structural diagram of the photodetector 120 according to an embodiment.
[0014] FIG. 3 is a flow-chart 300, which illustrates a process to fabricate the photodetector 120 according to an embodiment.
[0015] FIG 4 depicts a semi-log plot of current vs. voltage generated by the photodetector 120 according to an embodiment.
[0016] FIG 5 depicts a normalized signal generated by the photodetector 120 with reference to time according to an embodiment.
[0017] FIG 6 illustrates a system in which the photodetector 120 may be used according to an embodiment.
Detailed Description:
[0018] While the present invention is described herein with reference to illustrative embodiments for particular applications, it should be understood that the invention is not limited thereto. Those skilled in the relevant art(s) with access to the teachings provided herein will recognize additional modifications, applications, and embodiments within the scope thereof and additional fields in which embodiments of the present invention would be of significant utility.
[0019] Reference in the specification to “one embodiment”, “an embodiment” or “another embodiment” of the present invention means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrase “in one embodiment” or “in an embodiment” appearing in various places throughout the specification are not necessarily all referring to the same embodiment.
[0020] FIG. 1 depicts a photoemitter 110 and a photodetector 120, which is developed according to an embodiment. In one embodiment, the photoemitter 110 may be a source of light, which may provide a stream of photons 112. In one embodiment, the photodetector 120 may be designed and fabricated to sense the photons incident on the photodetector 120 and generate an electrical signal such as current (A). In one embodiment, the ability of the photodetector 120 to efficiently generate an electrical signal based on the light (or photons) incident on the photodetector 120 is enhanced using the techniques described below.
[0021] In one embodiment, the efficiency of the photodetector 120 may be enhanced by providing the spectral response over a broad frequency range. In one embodiment, the broad frequency range may vary from a visible band to enhanced infrared (IR) band (e.g., up to 2500nm). Additionally, in one embodiment, the photodetector 120 may provide high responsivity under zero bias, reduce noise, and enhance the range of operational wavelengths. Further, in one embodiment, the photodetector 120 may reduce the dark current (i.e., the current generated by the photodetector even when the light is not incident on the photodetector 120) to less than 10nA. In one embodiment, the photodetector 120 may quickly (in less than 6 milliseconds) provide response to the light incident on the photodetector 120.
[0022] FIG. 2 illustrates the structure of the photodiode 120 according to an embodiment of the current invention. In one embodiment, the photodetector 120 includes a substrate layer comprising a silicon base layer 210 and a silicon-dioxide layer 230 on top of the silicon base layer 210. In one embodiment, a thin layer of metal dichalcogenide 250, such as MoTe2, may be grown on the silicon-dioxide substrate. Antimony telluride (Sb2Te3) films may exhibit thermoelectric and optoelectrical properties. For example, Sb2Te3 films may exhibit broadband absorption and high carrier mobility in the infrared region, however conventional Sb2Te3-based photodetectors frequently suffer from limited photocurrent and reduced responsivity due to rapid carrier recombination. In one embodiment, to overcome such limitations, at least atop a portion of the thin layer of metal dichalcogenide 250, such as MoTe2, a layer of antimony telluride (Sb2Te3) films may be deposited using sputtering techniques.
[0023] In one embodiment, the combination of metal dichalcogenide 250, such as MoTe2, a layer of antimony telluride (Sb2Te3) films may create an improved carrier separation and may further result in reduced recombination without a need for an external bias voltage. In one embodiment, the heterojunction 257 formed at the junction of metal dichalcogenide 250, such as MoTe2, and a layer of antimony telluride (Sb2Te3) (illustrated by a dotted box) may generate a built-in-electric field, which may drive photocurrent under illumination and restrict photogenerated electron-hole pairs and the result of these two activities may enable self-powered operation. In one embodiment, the heterojunction may increase the extraction of photocurrent generated carriers while reducing recombination of electron-hole pairs based on the built-in electric field generated at the heterojunction. In one embodiment, the combination (or integration) of Sb2Te3 and MoTe2 films in a stacked heterostructure may provide broad spectral response, spanning from the visible range to the infrared (IR) band of up to 2500nm. In one embodiment, the optical absorption measurements reveal a bandgap of 0.7ev, which may correspond to an absorption range edge at 1.77 µm. In one embodiment, the band alignment the heterojunction may demonstrate enhanced absorption in the infrared ranges. In one embodiment, the bandgap voltage of 0.7eV (corresponding to an absorption range at 1.77 µm) corresponds to the observed photodetection performance.
[0024] In one embodiment, a schottky barrier may be formed when the electrodes (source) 280 comes in contact with Sb2Te3 and the electrodes (drain) comes in contact with the MoTe2 and a tunneling effect (or tunneling current) may be generated. In one embodiment, the Schottky barrier may be dependent on the metal work function. In one embodiment, the heterojunction 257 may be formed by a combination of an atomically thin layer (for example 200 nm), which may result in a minimum sized depletion region. In one embodiment, the minimum sized depletion layer may result in efficient separation of photocarriers (electron-hole pairs) resulting in minimal carrier recombination of electron-hole pairs and increases the photocurrent at the heterojunction 257 with the built-in electric field created at the P-N heterojunction 257. In one embodiment, the efficient separation of the photocarriers at the P-N heterojunction 257 may yield photocurrent across the P-N heterojunction 257 and as a result, a potential barrier in the forward direction of the flow of current in reduced significantly. In one embodiment, the lowering of the potential barrier in the forward direction significantly may enhance or increase the responsivity of the photodetector 120.
[0025] Thus, in one embodiment, the heterostructure comprising Sb₂Te₃ and MoTe₂ films allow for the strategic utilization of the built-in electric field at the P-N heterojunction 257 (Sb₂Te₃/MoTe₂ interface), which may enhance the charge carrier separation while reducing the rate of recombination, thus facilitating an efficient photodetection mechanism. In one embodiment, by operating the photodetector 120 in a self-powered mode and by extending the detection range to approximately 2500 nm, the photodetector 120 may be operated across a broadband of wavelengths. In one embodiment, additionally, the structure of the photodetector 120 described with reference to FIG. 2 may simplify the system architecture by eliminating the need for an external bias and may provide faster response times, thus making it a significant advancement in infrared photodetection technology.
[0026] In one embodiment, in summary, the photodetector 120 may fulfill the need for a broadband, high-performance, self-powered infrared photodetector using a Sb₂Te₃/MoTe₂ heterostructure that offers improved efficiency, extended spectral response, and reduced operational complexity.
[0027] FIG. 3 is a flow-chart illustrating a process or method of fabricating the photodetector 120 according an embodiment. In one embodiment, the process or method of fabricating a photodetector such as the photodetector 120 begins at block 310. In block 310, a silicon wafer 210 may be cleaned and as depicted in block 320, a silicon-dioxide 230 is formed for example, by a thermal oxidation process in which the silicon base layer 210 may be exposed to oxygen at high temperatures (e.g., 800-1200 degree centigrade). In one embodiment, the silicon base layer 210 reacts with oxygen and the silicon from the silicon base layer 210 diffuses to the surface while the oxygen species diffuses inwards into the silicon base layer 210 to forma a Si/SiO2 substrate. Even though the Silicon base layer 210 and silicon-dioxide substrate 230 is depicted as two layers, in practice, it may exist as a single layer, thus 210 and 230 together form a Si/SiO2 substrate. In one embodiment, the thickness of the Si/SiO2 substrate (210 and 230 together) with being 0.5mm and the thickness of SiO2 may be about 300nm.
[0028] In block 350, in one embodiment, a thin layer of MoTe2 film 250 may be grown on top of the Si/SiO2 substrate 230 (formed using the base layer 210. In one embodiment, the MoTe2 film 250 may be grown using a chemical vapor deposition (CVD) technique such as low- pressure CVD (LPCVD) or ultra vacuum CVD (UHVCVD) or any such other technique to grow MoTe2 film 250 on the substrate 230. In one embodiment, the CVD process may be used to produce high-quality and high-performance deposition of MoTe2 film 250 on the substrate 230.
[0029] In block 370, in one embodiment, Sb2Te3 layer 270 may be deposited atop at least a portion of the MoTe2 film 250 to form the P-N heterojunction 257. In one embodiment, the Sb2Te3 layer 270 may deposited atop MoTe2 film 250 using a sputtering technique at room temperature and under controlled pressure (approximately 5x10-2 mbar). In one embodiment, the sputtering may be preformed at a low sputtering power (for example, 5watts). In one embodiment, a shadow mask may be used to deposit Sb2Te3 layer 270 atop the MoTe2 film 250 to cover a portion of the MoTe2 film 250.
[0030] In block 380, in one embodiment, contacts 270 and 280 may be deposited on the MoTe2 film 250 and Sb2Te3 layer 270. In one embodiment, the contacts (or electrodes) may use Ti/Pt metal alloys. In one embodiment, the electrodes 270 may serve as source electrodes and the electrodes 280 may serve as drain electrodes. In one embodiment, the electrodes 270 coming in contact with the SbTe3 layer 270 may create ohmic contact and the electrodes 280 coming in contact with MoTe2 film 250 may form a Schottky barrier.
[0031] FIG. 4 illustrates a normalized plot of the voltage vs the current generated by the photodetector 120 according to an embodiment. In one embodiment, in the graph 400, x- axis depicts the voltage V ranging from -2.5V to + 2.5V and the y-axis depicts the current ranging from !0-10 to 10-4 amps. As may be readily seen, the plot 460 represents a photocurrent in the absence of a heterojunction 257 formed at the interface of MoTe2 and Pb2Te3 as described in FIG. 2 and FIG. 3. Due to quicker recombination electron-hole pairs, the current at a bias voltage value of -2.5V is about 10-8 amps as compared to increased photocurrent of 10-5 as depicted by the plot 450. In one embodiment, the plot 450 illustrates the response of the photodetector 120 formed as described in FIGs.2 and 3 above. As can be seen from the plot 460, the photocurrent decreases from 10-8 amps to 10-10 amps (between-2.5V and 0 volts) and then increases to 10-5 amps when a positive voltage is ranging from 1V to 2.5V is applied. In one embodiment, the plot 450 depicts the impact of having a heterojunction 257 formed at the interface of MoTe2 and Pb2Te3 layers. In one embodiment, as can be seen from the plot 450, the photocurrent has increased to 10-5 amps at -2.5V and the current value decreases to 10-10 amps (dark current, which is substantially low and thus the noise levels are low as well) when the voltage at across the heterojunction 257 is zero and then increases to 10-4 amps while the voltage increases from 1V to 2.5V. As can be observed, in comparison, the response (i.e., the photocurrent generated for voltage -2.5V to 0V) of the photodetector 120 is substantially higher (10-5 amps at -2.5V in plot 450 as compared to 10-8 amps at -2.5V in plot 460) as that of a photodetector, which may not include a heterojunction such as the heterojunction 257. Thus, in one embodiment, the photodetector built using the techniques described above lead to an efficient photodetector 120.
[0032] FIG. 5 illustrates a graph 500, which depicts a normalized response of the photodetector 120 measured against time (in seconds) under zero-bias operation. In one embodiment, the experimental set-up used to measure the response of the photodetector 120 may include a 730 nm LED as the illumination source. In one embodiment, in the graph, the “0” state corresponds to the LED being turned on, while the “1” state represents the LED being turned off. In one embodiment, sharp transitions between these states indicate a fast photoresponse, suggesting efficient carrier separation and collection without the need for an external bias. In one embodiment, a stable and repeatable switching behaviour further confirms the photodetector 120’s reliability and high sensitivity, thus making it suitable for self-powered photodetection applications.
[0033] FIG. 6 illustrates a graph 600, which depicts the variation of current with reference to time according to an embodiment. As may be observed from the response of the photodetector 1200, the photodetector 120 may be capable of detecting wavelengths up to 2500nm. In one embodiment, this extended detection range (from visible to 2500nm) may be due to the engineered Sb₂Te₃/MoTe₂ heterostructure, which may enhance the infrared absorption (1.77 µm). In one embodiment, the heterojunction 257 bandgap, determined to be ~0.7 eV from optical absorption, aligns with the observed photodetection. Additionally, the built-in electric field at the interface aids carrier separation, improving responsivity without external bias.
[0034] FIG. 7 illustrates a system 700, which includes an antenna 705, a transceiver 710, processor hub 720, a communication processor 730, a memory 740, a photoemitter 750, and a photodetector 770. In one embodiment, the transceiver 710 may include a transmitter and a receiver combination, which may include blocks such as radio frequency front end, power amplifiers, low noise amplifiers and such other blocks to transmit to and receive signals from other devices. In one embodiment, the transceiver 710 may receive or transmit radio frequency (RF) signals using the antenna 705. In one embodiment, the transceiver 710 may receive optical signals from the photodetector 770 and transmit photon signals using the photo emitter 750.
[0035] In one embodiment, the transceiver 710 may process the signals using the RF chains included in the transceiver 710 using the signals received from the communication processor 720 while transmitting and may provide the signals to the communication processor 720 while receiving the signals. In one embodiment, the communication processors 730 may include base band processors, Wi-Fi processors, Bluetooth processors and other processors, which may support wireless and wired transmissions between the system 700 and other systems. In one embodiment, the communication processor 720 may receive signals from the transceiver 710 and process the signals and either generate a signal to be transmitted or may send the signals to the processor hub 730 for further processing. In one embodiment, the communication processor720 may receive data or signals from the processor hub 730 and may processor such signals before sending the processed signals to the transceiver 710.
[0036] In one embodiment, the processor hub 720 may include a central processing unit (CPU), a graphics processing unit (GPU), a neuromorphic processing unit, AI processors, and AI accelerators. In one embodiment CPU may be a complex instruction set (CISC) or reduced instruction set (RISC) based processor and may support massively parallel processing, hyper threading, virtual machine monitors and such other techniques. The GPU may be a special set of processors suited to process graphics workloads. The neuromorphic processing unit (NPU) may be a specialized processor that mimics the human brain's neural network. NPU may be designed to perform AI tasks and workloads, such as speech recognition, natural language processing, and object detection. NPU may include AI processors and and/or AI accelerators. In one embodiment, the processor hub 730 may store the data, instructions in the memory 740 and retrieve the software instructions and /or data from the memory 740 as required. In one embodiment, the memory 740 may include SRAM, DRAM, DDR, DDDR, NV, SSID and such other memory blocks. The memory may store instructions to provide a controlled manufacturing environment for fabricating and manufacturing the photodetectors 120 as depicted in FIGs 2 and 3 and the processor hub 720 may use the instructions stored in the memory 740 to control the manufacturing processes to fabricate the photodetector 120 as described in FIGs 2 and 3.
[0037] In one embodiment, the photoemitter 750 may receive a signal from the transceiver 710 and converter the signal into optical signal or light signal or a stream of photos and emit the photon stream. In one embodiment, the photoemitter 750 may include, for example, a light emitting diode (LED) or such other light emitting devices.
[0038] In one embodiment, the photodetector 770 may include a photodetector such as the photodetector 120 as described above. In one embodiment, the photodetector 770 may be constructed using MoTe2 and Sb2Te3 films grown and/or deposited over the Si/Sio2 substrate as described above with reference to FIG.2 and FIG. 3. In one embodiment, the photodetector 770 (or 120) may enable higher efficiencies by enabling zero-bias operation and decreasing the amount of dark current (for example, to 10-9 or 10-10 amps, please sure plot 450 of FIG. 4 at 0 V) while increasing the photo current (e.g., to 10-5 amps, please sure plot 450 of FIG. 4 at -3 V) resulting in high signal-to-noise ratio (SNR) and responses over broad range of wavelengths (visible to up to 2500 nm) at high responsivity (e.g., 6 milliseconds). In one embodiment, the photodetector 770 (or the photodetector 120) may be included in the devices such as infrared cameras, environmental monitoring systems for gas detection in the infrared range, optical communication systems operating in near-infrared ranges, security and surveillance systems including night vision cameras, for example, automotive LiDARs, wearable sensors, machine vision, medical devices, equipment used in oil and gas extraction and processing. In one embodiment, the photodetector 770 (or 120) may be self-powered, operating over a broad range of wavelengths, available at low-cost thus offering a reduced power consumption and simple to integrate solutions.
[0039] Embodiments according to the disclosure are in particular disclosed in the attached claims directed to a method, a storage medium, a device and a computer program product, wherein any feature mentioned in one claim category, e.g., method, can be claimed in another claim category, e.g., system, as well. The dependencies or references back in the attached claims are chosen for formal reasons only. However, any subject matter resulting from a deliberate reference back to any previous claims (in particular multiple dependencies) can be claimed as well, so that any combination of claims and the features thereof are disclosed and can be claimed regardless of the dependencies chosen in the attached claims. The subject-matter which can be claimed comprises not only the combinations of features as set out in the attached claims but also any other combination of features in the claims, wherein each feature mentioned in the claims can be combined with any other feature or combination of other features in the claims. Furthermore, any of the embodiments and features described or depicted herein can be claimed in a separate claim and/or in any combination with any embodiment or feature described or depicted herein or with any of the features of the attached claims.
[0040] The foregoing description of one or more implementations provides illustration and description but is not intended to be exhaustive or to limit the scope of embodiments to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of various embodiments.
[0041] Certain aspects of the disclosure are described above with reference to block and flow diagrams of systems, methods, apparatuses, and/or computer program products according to various implementations. It will be understood that one or more blocks of the block diagrams and flow diagrams, and combinations of blocks in the block diagrams and the flow diagrams, respectively, may be implemented by computer-executable program instructions. Likewise, some blocks of the block diagrams and flow diagrams may not necessarily need to be performed in the order presented or may not necessarily need to be performed at all, according to some implementations.
[0042] These computer-executable program instructions may be loaded onto a special-purpose computer or other particular machine, a processor, or other programmable data processing apparatus to produce a particular machine, such that the instructions that execute on the computer, processor, or other programmable data processing apparatus create means for implementing one or more functions specified in the flow diagram block or blocks. These computer program instructions may also be stored in a computer-readable storage media or memory that may direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable storage media produce an article of manufacture including instruction means that implement one or more functions specified in the flow diagram block or blocks. As an example, certain implementations may provide for a computer program product, comprising a computer-readable storage medium having a computer-readable program code or program instructions implemented therein, said computer-readable program code adapted to be executed to implement one or more functions specified in the flow diagram block or blocks. The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational elements or steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions that execute on the computer or other programmable apparatus provide elements or steps for implementing the functions specified in the flow diagram block or blocks.
[0043] Accordingly, blocks of the block diagrams and flow diagrams support combinations of means for performing the specified functions, combinations of elements or steps for performing the specified functions and program instruction means for performing the specified functions. It will also be understood that each block of the block diagrams and flow diagrams, and combinations of blocks in the block diagrams and flow diagrams, may be implemented by special-purpose, hardware-based computer systems that perform the specified functions, elements or steps, or combinations of special-purpose hardware and computer instructions.
[0044] Conditional language, such as, among others, “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain implementations could include, while other implementations do not include, certain features, elements, and/or operations. Thus, such conditional language is not generally intended to imply that features, elements, and/or operations are in any way required for one or more implementations or that one or more implementations necessarily include logic for deciding, with or without user input or prompting, whether these features, elements, and/or operations are included or are to be performed in any particular implementation.
[0045] Many modifications and other implementations of the disclosure set forth herein will be apparent having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the disclosure is not to be limited to the specific implementations disclosed and that modifications and other implementations are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
, Claims:We Claim:
1. A photodetector (120, 770), comprising:
a substrate;
a metal dichalcogenide film grown on top of the substrate;
an antimony telluride deposited atop at least a portion covering the metal dichalcogenide film to form a heterojunction at the interface of metal dichalcogenide film and the antimony telluride, wherein the heterojunction is to increase extraction of photocurrent generated carriers while reducing recombination of electron-hole pairs based on the built-in electric field generated at the heterojunction; and
one or more first electrodes coupled to the metal dichalcogenide film and one or more second electrodes coupled to the antimony telluride.

2. The photodetector as claimed in claim 1, wherein the metal dichalcogenide film includes molybdenum ditelluride (MoTe2).

3. The photodetector as claimed in claim 1, wherein the heterojunction enables the photodetector to operate upto to a wavelength of 2500nm.

4. The photodetector as claimed in claim 1, wherein the heterojunction enables the photodetector to operate over a broad range of wavelengths ranging between 400nm and 2500 nanometer (nm).

5. The photodetector as claimed in claim 1, wherein the band alignment at the heterojunction increases the absorption (1.77 µm) in the infrared range.

6. The photodetector as claimed in claim 1, wherein the heterojunction enhances optical absorption, based on a bandgap voltage of about ~0.7 eV.

7. The photodetector as claimed in claim 1, wherein the band alignment in the heterojunction to improve the carrier separation to enhance a photocurrent flow.

8. The photodetector as claimed in claim 1, wherein the heterojunction is formed by physical vapor deposition of a layer of the Sb2Te3 layer atop at least a portion of molybdenum ditelluride (MoTe2).

9. The photodetector as claimed in claim 1, wherein the heterojunction is formed by sputtering a layer of the Sb2Te3 layer of thickness of up to 200 nm, wherein the physical vapor deposition includes sputtering.

10. The photodetector as claimed in claim 1, wherein the heterojunction to create the built-in electric field to drive photocurrent under illumination to enable a self-powered operation.

11. A method to fabricate a photodetector, the method comprising:
clean a silicon wafer;
create a Si/Sio2 substrate based on oxidization of the silicon wafer by oxygenating the silicon wafer;
grow a thin film of molybdenum ditelluride (MoTe₂) using a controlled CVD (Chemical Vapor Deposition) technique to ensure uniform thickness and high-quality crystallinity;
deposit antimony telluride (Sb₂Te₃) is deposited atop the MoTe₂ film at room temperature under a controlled pressure and low sputtering power; and
couple one or more first set of electrodes to the Sb2Te3 and one or more second set of electrodes to the MoTe2 film to form robust electrical contacts.

12. The method of claim 13, wherein a heterojunction is formed at the interface of molybdenum telluride (MoTe₂) and antimony telluride (Sb₂Te₃).

13. The method of claim 13, wherein the interface of molybdenum telluride (MoTe₂) and antimony telluride (Sb₂Te₃) is to form a P-N heterojunction.

14. The method of claim 13, wherein the antimony telluride (Sb₂Te₃) is deposited using a physical vapor deposition technique.

15. The method of claim 16, wherein the antimony telluride (Sb₂Te₃) is deposited using a sputtering technique, which is performed at the room temperature and under controlled pressure, wherein the physical vapor deposition technique includes sputtering.

16. The method of claim 16, wherein the antimony telluride (Sb₂Te₃) is deposited using physical vapor deposition technique, which is performed at the room temperature and under controlled pressure of 5x10-2 mbar.

17. The method of claim 16, wherein the antimony telluride (Sb₂Te₃) is deposited using physical vapor deposition technique, which is performed at low sputtering power.

18. The method of claim 16, wherein the antimony telluride (Sb₂Te₃) is deposited using physical vapor deposition technique, which is performed at low sputtering power of 5 watts.
19. The method of claim 13, wherein a contact between the one or more first set of electrodes and the Sb2Te3 to form an ohmic contact between the one or more first set of electrodes and the Sb2Te3.
20. The method of claim 13, wherein a contact between the one or more second set of electrodes and the MoTe2 film to form the Schottky barrier.
21. A photodetector comprising:
a silicon/silicon dioxide (Si/SiO2) substrate;
a molybdenum ditelluride (MoTe₂) layer stacked on top of the silicon/silicon dioxide (Si/SiO2) substrate;
an antimony telluride (Sb₂Te₃) layer stacked on top of at least a portion of the MoTe₂; and
one or more first set of electrodes coupled to the Sb2Te3 and one or more second set of electrodes coupled to the MoTe2 film to form electrical contacts.
22. The photodetector of claim 21, wherein a heterojunction is formed at the interface of MoTe₂ and Sb₂Te₃.
23. The photodetector of claim 21, wherein the photodetector to operate between 400nm and 2500nm.