1. A field-effect transistor comprising at least:
a substrate;
a source electrode;
a drain electrode;
a gate electrode;
a semiconductor layer in contact with the source electrode and with the drain electrode; and
a gate insulating layer insulating between the semiconductor layer and the gate electrode,
the semiconductor layer comprising an organic semiconductor and/or a carbon material, and
the gate insulating layer comprising at least a polysiloxane having a structural unit represented by a general formula (1):
in the general formula (1), R1 represents a hydrogen atom, an alkyl group, a cycloalkyl group, a heterocyclic group, an aryl group, a heteroaryl group, or an alkenyl group; R2 represents a hydrogen atom, an alkyl group, a cycloalkyl group, or a silyl group; m represents 0 or 1; A1 represents an organic group including at least two groups selected from a carboxy group, a sulfo group, a thiol group, a phenolic hydroxy group, or a derivative of these groups; when the derivative is a cyclic condensed structure formed by two groups out of the carboxy group, the sulfo group, the thiol group, and the phenolic hydroxy group, A1 represents an organic group having at least one the cyclic condensed structure.

2. The field-effect transistor according to claim 1, wherein A1 in the general formula (1) is an organic group having at least two carboxy groups or derivatives of the carboxy groups, or an organic group having at least one cyclic acid anhydride group.
3. The field-effect transistor according to claim 1 or 2, wherein
A in the general formula (1) is a group represented by a following general formula (2) or (3):
in the general formula (2), X1 represents a single bond, an alkylene group having 1 to 10 carbon atoms, or an arylene group having 6 to 15 carbon atoms; R3 and R4 represent independently a hydrogen atom, an organic group, or a silyl group; in the general formula (3), X2 represents a single bond, an alkylene group having 1 to 10 carbon atoms, or an arylene group having 6 to 15 carbon atoms.
4. The field-effect transistor according to any one of claims 1 to 3, wherein the polysiloxane contains the structural unit represented by the general formula (1) with a rate of at least 0.5% by mole and up to 20% by mole relative to entire silane structural units.
5. The field-effect transistor according to any one of claims 1 to 4, wherein the polysiloxane further has a

structural unit represented by a following general formula (4) :
in the general formula (4), R5 represents a hydrogen atom, an alkyl group, a cycloalkyl group, a heterocyclic group, an aryl group, a hetero-aryl group, or an alkenyl group; R6 represents a hydrogen atom, an alkyl group, a cycloalkyl group, or a silyl group; n represents 0 or 1; B1 represents an organic group including an addition reaction structure formed among an acryl group and/or a methacryl group themselves.
6. The field-effect transistor according to claim 5, wherein the polysiloxane contains the structural unit represented by the general formula (4) with a rate of at least 5% by mole and up to 50% by mole relative to entire silane structural units.
7. The field-effect transistor according to any one of claims 1 to 6, wherein the semiconductor layer includes a carbon nanotube.
8. The field-effect transistor according to claim 7, wherein the carbon nanotube includes a carbon nanotube composite having a conjugated polymer attached to at least part of surface of the carbon nanotube.
9. The field-effect transistor according to any one of claims 1 to 8, wherein the source electrode, the drain

electrode, and/or the gate electrode include(s) an organic binder and an electric conductive body.
10. The field-effect transistor according to any one of claims 1 to 9, wherein the gate insulating layer includes a metal compound having a bond between a metal atom and an oxygen atom.
.11. A method for producing the field-effect transistor 3 according to any one of claims 1 to 10, the method comprising:
(I) a step of forming an electric conductive pattern
on a substrate;
(II) a step of applying a solution including at least
a polysiloxane having a structural unit represented by the
general formula (1) onto the substrate having the electric
conductive pattern formed thereon, followed by drying; and
(III) a step of applying a solution including an
organic semiconductor and/or a carbon material so as to be
in contact with the electric conductive pattern, followed
by drying.
12. The method for producing the field-effect transistor according to claim 11, the method comprising:
(I) a step of forming an electric conductive pattern on a substrate,
(II-A) a step of irradiating a film with active actinic light via a photomask, the film being obtained by applying onto the substrate having the electric conductive pattern formed thereon a solution including at least the polysiloxane having the structural unit represented by the general formula (1) and a photosensitive organic component followed by drying, followed by forming of a pattern
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turning into an opening on the electric conductive pattern using an alkali solution,
(II-B) a step of heating the pattern to form a cured pattern, and
(III) a step of applying a solution including an organic semiconductor and/or a carbon material so as to be in contact with the electric conductive pattern, followed by drying.
13. The method for producing the field-effect transistor according to claim 12, wherein the photosensitive organic component comprises a compound generating a radical by light and a radical polymerizable compound.
14. The method for producing the field-effect transistor according to claim 12, wherein the photosensitive organic component comprises a compound generating an acid by light.
15. A wireless communication device comprising the field-effect transistor according to any one of claims 1 to 10.
16. A goods tag comprising the wireless communication device according to claim 15.