[0001] The present disclosure relates generally to field of plasmonics. More particularly, the present disclosure provides a plasmonic based photo detector for enhancement of light absorption.

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art. Recent era of high speed photonic system demands photo detector to have large bandwidth, gain and better light enhancement competence with miniaturization of device. Amongst different light absorption enhancement methods being examined by investigators, plasmonic has acquired a lot of attention in last years. When light is falling on front surface of conventional type metal semiconductor metal photo detectors, the light generates electron–hole pairs and produce output current. However, major drawback of this conventional photo detector is that when light is incident on the front surface then maximum amount of the light is reflected back, resulting in light reflection losses and reduces efficiency of device. To overcome this problem, Plasmonic based photo detector using single layer nanogratings came into existence with gold material. These nanogratings are used to couple more light. So using nanogratings, minimization in the reflection losses is achieved. There are proposed material and shape for plasmonic device such as silver material for nanogratings, triangular shape of nanogratings, crystalline silicon embedded with silver material for nanoparticles (NPs), trapezoidal shape of nanoparticles and gallium phosphide (GaP) for substrate. However, gold is very costly so other noble material which can be used in place of gold is Silver. Table.1 represents that the damping rate of silver material is less than other material. Also, intraband transitions (eV) of silver material is 3.9 i.e., higher than energy of photons. So, silver can be a promising material for nanogratings in plasmonic applications. The best choice of material for plasmonic application is one that has the minimum losses means less damping rate. Also, intraband transitions (eV) should be greater than energy of the plasmons (1.8eV to 3.1eV). Various researchers obtained the plasmonic device using gold material with single layer of rectangular nanogratings. However, triangular nanogratings with silver material are never used yet in research. Light trapping phenomenon is higher in case of triangular nanogratings as compared to rectangular nanogratings. Moreover, surface plasmon resonance is easily obtained with triangular nanogratings. The absorption area of a plasmonic MSM-PD structure can also be increased through the use of metal nanoparticles embedded onto the semiconductor substrate. It is well known that the conduction electrons of such metal nanoparticles induce light-stimulated resonance that enhances optical absorption. This phenomenon is known as localized surface plasmon resonance (LSPR), because it occurs within the nanoparticles. Light trapping within the device also depends upon nanoparticles shape and material. For this, we proposed the trapezoidal shape for crystalline silicon embedded with silver NPs to enhance the light trapping.
[0003] There are other possible solutions, where noble material can be changed. However, from table, it can be observed that if noble material is changed, damping rate increases which is not suitable for plasmonic applications.

Material Damping rate (eV) Intraband transitions (eV)
Silver 0.02 3.9
Gold 0.07 2.3
Aluminum 0.13 1.41

[0004] There is a need to overcome above mentioned problem of prior art by bringing a solution that facilitates obtaining higher output, is cost-effective device, and more efficient in case of light absorption with surface plasmonic resonance. Also, the solution is used for night vision applications.

OBJECTS OF THE PRESENT DISCLOSURE
[0005] Some of the objects of the present disclosure, which at least one embodiment herein satisfies are as listed herein below.
[0006] It is an object of the present disclosure to provide a plasmonic detector where material used for nanogratings is less costly as compared to gold.
[0007] It is an object of the present disclosure to provide a plasmonic based photo detector that has less damping rate than other noble material.
[0008] It is an object of the present disclosure to provide a plasmonic based photo detector where the nanogratings and nanoparticles shape have superior light trapping characteristics because of surface plasmon resonance.
[0009] It is an object of the present disclosure to provide a plasmonic based photo detector with higher light absorption capacity due to triangular silver nanogratings and crystalline silicon embedded with silver nanoparticles.
[0010] It is an object of the present disclosure to provide a plasmonic based photo detector that can be used for night vision applications and gives the higher output in terms of light absorption enhancement factor (LAEF) with help of the triangular nanogratings.

SUMMARY
[0011] The present disclosure relates generally to field of plasmonics. More particularly, the present disclosure provides a plasmonic based photo detector for enhancement of light absorption.
[0012] An aspect of the present disclosure pertains to a plasmonic based photo detector for enhancement of light absorption; the photo detector may include a substrate, a first layer and a second layer. The first layer may be configured on top of the substrate, where the first layer may be made up of a first material with predefined number of trapezoidal shaped nano particles. The second layer may be configured on top of the first layer, where the second layer may be made up of a second material with predefined number of triangular shaped nanograting particles. The second layer may be configured with an aperture of predefined wavelength, where the aperture may facilitate enhancing light transmission to the substrate, and where the photdetector may facilitate achieving a high light absorption enhancement factor (LAEF).
[0013] In an aspect, the first material may be made up of any or a combination of silver, gold and platinum.
[0014] In an aspect, the second material may be made up of any or a combination of crystalline silicon and cadmium telluride.
[0015] In an aspect, the predefined number of triangular shaped nanogratings may include five nonogratings.
[0016] In an aspect, dimensions of the predefined number of triangular shaped nanograting particles may include height of fifty nanometers and width of twenty nanometer.
[0017] In an aspect, dimensions of the predefined number of trapezoidal shaped nanoparticles may include height of twenty nanometers and width of seventeen nanometer.
[0018] In an aspect, the predefined wavelength may includes a range from one point one micrometer to one point five five micrometer.
[0019] In an aspect, the first aperture height may be of forty nanometer.
[0020] In an aspect, the substrate may be made up of gallium phosphide (GaP) material substrate.
[0021] In an aspect, dimensions of the substrate may include height of three hundred and sixty nanometer and width of one thousand, two hundred and fifty nanometer.

BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0023] The diagrams are for illustration only, which thus is not a limitation of the present disclosure, and wherein:
[0024] FIG. 1A and FIG. 1B illustrate an exemplary diagram and graphical representation of proposed plasmonic based photo detector, for enhancement of light absorption, in accordance with an embodiment of the present disclosure.

DETAIL DESCRIPTION
[0025] In the following description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. It will be apparent to one skilled in the art that embodiments of the present invention may be practiced without some of these specific details.
[0026] Embodiments of the present invention include various steps, which will be described below. The steps may be performed by hardware components or may be embodied in machine-executable instructions, which may be used to cause a general-purpose or special-purpose processor programmed with the instructions to perform the steps. Alternatively, steps may be performed by a combination of hardware, software, firmware and/or by human operators.
[0027] If the specification states a component or feature “may”, “can”, “could”, or “might” be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
[0028] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0029] While embodiments of the present invention have been illustrated and described, it will be clear that the invention is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents will be apparent to those skilled in the art, without departing from the spirit and scope of the invention, as described in the claim.
[0030] The present disclosure relates generally to field of plasmonics. More particularly, the present disclosure provides a plasmonic based photo detector for enhancement of light absorption.
[0031] FIG. 1A and FIG. 1B illustrate an exemplary diagram and graphical representation of proposed plasmonic based photo detector, for enhancement of light absorption, in accordance with an embodiment of the present disclosure.
[0032] As illustrated in FIG. 1A, the plasmonic based photo detector (100) (also referred to as photo detector (100), herein) can facilitate enhancing light absorption. The photo detector (100) can include a substrate (108), a first layer (106) and a second layer (102). The first layer (106) can be configured on top of the substrate (108), where the first layer (106) can be made up of a first material with predefined number of trapezoidal shaped nano particles. The second layer (102) can be configured on top of the first layer (106), where the second layer (102) can be made up of a second material with predefined number of triangular shaped nanograting particles. The second layer (102) can be configured with an aperture (104) of predefined wavelength, where the aperture (104) can facilitate enhancing light transmission to the substrate (108), and where the photo detector (100) can facilitate achieving a high light absorption enhancement factor (LAEF).
[0033] In an exemplary embodiment, the first material can be made up of any or a combination of silver, gold, platinum, and the likes. In another exemplary embodiment, the second material can be made up of any or a combination of crystalline silicon, cadmium telluride, and the likes.
[0034] In an exemplary embodiment, the predefined number of triangular shaped nanogratings can include five nonogratings, but not limited to the likes. In another exemplary embodiment, dimensions of the predefined number of triangular shaped nanograting particles can include height of fifty nanometer and width of twenty nanometer, but not limited to the likes. In yet another exemplary embodiment, dimensions of the predefined number of trapezoidal shaped nano particles can include height of twenty nanometers and width of seventeen nanometer, but not limited to the likes.
[0035] In an exemplary embodiment, the predefined wavelength can include a range from one point one micrometer to one point five five micrometer. In another exemplary embodiment, the aperture height can be of forty nanometer.
[0036] In an exemplary embodiment, the substrate (108) can be made up of gallium phosphide (GaP) material substrate, but not limited to the likes. In another exemplary embodiment, dimensions of the substrate (108) can include height of three hundred and sixty nanometres and width of one thousand, two hundred and fifty nanometers, but not limited to the likes.
[0037] In an illustrative embodiment, the predefined number of the triangular shaped nanogratings can be used for light coupling or also called as wave collector. Initially light can be incident on a metal surface where predefined number of the triangular shaped nanogratings can be used to couple the maximum light and transmit through the aperture of the predefined wavelength. Then the light can be transmitted through the aperture of the predefined wavelength into the first layer configured with the predefined number of the trapezoidal shaped nano particles. The predefined number of the trapezoidal shaped nano particles can be configured to distribute incoming light inside the substrate (108) in wider area and maximum light distribution can facilitate enhancing the light absorption within the photo detector (100) and thereby increases output. In another illustrative embodiment, light distribution with predefined number of the trapezoidal shaped nano particles is higher.
[0038] In an illustrative embodiment, the substrate (108) can be made up of gallium phosphide (GaP) semiconductor, where the GaP enables absorbing light in photo detector (100). In another illustrative embodiment, the second layer (102) can be single layer of predefined number of triangular nanogratings to capture large amount of the light or enhance the light trapping for more light absorption. In yet another illustrative embodiment, the second layer (102) made up of the second material, where the second material can be plasmonic material i.e., silver for predefined number of triangular shaped nanogratings owing to low cost, low damping rate and higher intraband transitions characteristics for better performance of the photo detector (100).
[0039] In an illustrative embodiment, the first layer (106) can be made up of the first material, where the first material can be crystalline silicon material embedded with predefined number of the trapezoidal shaped silver nanoparticles for wider distribution of incoming light into the GaP substrate (108). In another illustrative embodiment, the photo detector (100) configured with predefined number of the triangular shaped nanogratings and the predefined number of the trapezoidal shaped nanoparticles can facilitate providing high response and better sensitivity, where electromagnetic field confinement occurs for the photo detector (100). In yet another illustrative embodiment, single-layered predefined number of triangular shaped nanogratings can facilitate reducing optical losses and enhances light absorption efficiency.
[0040] In an illustrative embodiment, the photo detector (100) can facilitate achieving higher absorption in near infrared region at a predefined wavelength of one point four micrometer. To analyze performance of the photo detector (100), there is light absorption enhancement factor (LAEF) which can determine performance of photo detector. Light absorption enhancement factor can be defined as ratio of power transmittance with nanogratings to power transmittance without the predefined number of the triangular shaped nanogratings. In another illustrative embodiment, the photo detector (100) with predefined number of triangular shaped nanogratings can be simulated using OptiFDTD tool. To obtain the LAEF factor, a simulation tool like OptiFDTD can be used, where the OptiFDTD can include predefined input parameters which are used during simulations. The predefined input parameters include any or a combination of predefined number of triangular shaped nano gratings, predefined number of triangular shaped nanograting height, predefined number of triangular shaped nanogratings width, predefined wavelength, aperture height, substrate material, number of triangular shaped nanogratings, predefined number of trapezoidal shaped nanoparticle height, predefined number of trapezoidal shaped nanoparticle width, and substrate dimensions.
[0041] In an illustrative embodiment, the OptiFDTD simulation tool can include an input vertical plane (110), where the input vertical plane (110) can be configured to provide input light wavelength which lies in near-infrared region as from OptiFDTD simulation tool. The predefined input parameters can be used in nanometer scale for miniaturization of optical components and high responsivity of the photo detector (100).
[0042] As illustrated in Table, where the table can depict the LAEF of the photo detector (100) which indicates higher LAEF i.e., six point five six seven at one point four micrometer (6.567 at 1.4µm). the table also shows comparison between proposed results of predefined number of silver based triangular nanogratings with existing literature results of silver based rectangular nanogratings (LAEF i.e., 3.724), where the table helps in analyzing higher absorption achieved with resonance phenomenon in case of predefined number of triangular shaped nanogratings owing to better light trapping at one point four micrometer (1.4µm).

Input Wavelength (µm) LAEF with Rectangular
(Literature) LAEF with Triangular (Proposed)
1.1 1.156 1.357
1.2 1.546 2.573
1.3 1.724 4.573
1.33 2.567 5.349
1.4 3.724 6.567
1.5 2.489 4.892
1.55 2.056 3.834

[0043] In an illustrative embodiment, silver material used for the predefiend number of triangular nonogratings is less costly as compared to gold and damping ration of silver material is less as compared to the gold damping ratio. Also, the predefiend number of triangular shaped nanogratings and the predefined number of trapezoidal shaped nanoparticles can have superior light trapping characteristics because of surface plasmon resonance, and facilitate achieving higher light absorption with predefined number of triangular shaped silver nanogratings and crystalline silicon embedded with predefined number of trapezoidal shaped silver nanoparticles. The predefined number of the trapezoidal shaped nanoparticles can play an important role to capture more light. In another illustrative embodiment, the photo detetor (100) can be used for night vision applications and gives higher output in terms of LAEF. Maximum output can be (LAEF i.e., 6.567) obtained with predefined number of triangular shaped nanogratings.
[0044] In an embodiment, FIG. 1B illustrate the graphical representation of the plasmoninc based photo detector (100) with x axis scale and y axis scale in nanometer, where the plasmoninc based photo detector (100) can include a substrate (108), a first layer (106) configured on top of the substrate (108), where the first layer (106) can be made up of a first material with predefined number of trapezoidal shaped nano particles, a second layer (102) configured on top of the first layer (106), where the second layer (102) can be made up of a second material with predefined number of triangular shaped nanograting particles. The second layer (102) can be configured with an aperture (104) of predefined wavelength, where the aperture (104) can facilitate enhancing light transmission to the substrate (108) and where the photo detector (100) can facilitate achieving a high light absorption enhancement factor (LAEF).
[0045] In an illustrative embodiment, the predefined number of the triangular nanogratigns and the predefined number of the trapezoidal shaped nanoparticles can have dimensions in range of nanometer, and the predefined input parameters associated with the OptiFTFD simulation tool can be measured in nanometer with help of the X axis and Y axis. The graphical representation can include an input vertical plane (110), where the input vertical plane (110) can be configured to provide input light wavelength which lies in near-infrared region as from OptiFDTD simulation tool. The predefined input parameters can be used in nanometer scale for miniaturization of optical components and high responsivity of the photo detector (100).

ADVANTAGES OF THE PRESENT DISCLOSURE
[0046] The present disclosure provides a plasmonic based photo detector where material used for nanogratings is less costly as compared to gold.
[0047] The present disclosure provides a plasmonic based photo detector that has less damping rate than other noble material.
[0048] The present disclosure provides a plasmonic based photo detector where the nanogratings and nanoparticles shape have superior light trapping characteristics because of surface plasmon resonance.
[0049] The present disclosure provides a plasmonic based photo detector with higher light absorption capacity due to triangular silver nanogratings and crystalline silicon embedded with silver nanoparticles.
[0050] The present disclosure provides a plasmonic based photo detector that can be used for night vision applications and gives the higher output in terms of light absorption enhancement factor (LAEF) with help of the triangular nanogratings.

Claims:1. A plasmonic based photo detector (100) for enhancement of light absorption, said photo detector (100) comprising
a substrate (108);
a first layer (106) configured on top of the substrate (108), wherein the first layer (106) is made up of a first material with predefined number of trapezoidal shaped nano particles;
a second layer (102) configured on top of the first layer (106), wherein the second layer (102) is made up of a second material with predefined number of triangular shaped nanograting particles,
wherein the second layer (102) is configured with an aperture (104) of predefined wavelength, wherein the aperture (104) facilitates enhancing light transmission to the substrate (108),
and wherein the photo detector (100) facilitates achieving a high light absorption enhancement factor (LAEF).
2. The plasmonic based photo detector (100) as claimed in claim 1, wherein the first material is made up of any or a combination of silver, gold and platinum.
3. The plasmonic based photo detector (100) as claimed in claim 1, wherein the second material is made up of any or a combination of crystalline silicon and cadmium telluride.
4. The plasmonic based photo detector (100) as claimed in claim 1, the predefined number of triangular shaped nanogratings includes five nonogratings.
5. The plasmonic based photo detector (100) as claimed in claim 1, wherein dimensions of the predefined number of triangular shaped nanograting particles include height of fifty nanometer and width of twenty nanometer.
6. The plasmonic based photo detector (100) as claimed in claim 1, wherein dimensions of the predefined number of trapezoidal shaped nanoparticles include height of twenty nanometer and width of seventeen nanometer.
7. The plasmonic based photo detector (100) as claimed in claim 1, wherein the predefined wavelength includes a range from one point one micrometer to one point five five micrometer.
8. The plasmonic based photo detector (100) as claimed in claim 1, wherein the aperture (104) height is of forty nanometer.
9. The plasmoninc based photo detector (100) as claimed in claim 1, wherein the substrate (108) is made gallium phosphide (GaP) material substrate.
10. The plasmoninc based photo detector (100) as claimed in claim 9, wherein dimensions of the substrate (108) include height of three hundred and sixty nanometer and width of one thousand, two hundred and fifty nanometer.