# US 8,569,746 B2 · Organic field effect transistor

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- Number: US 8,569,746 B2
- Document ID: US8569746B2
- Status: Granted
- Kind: B2
- Application number: 13/001,585
- Filed: 2009-06-04
- Published: 2011-05-05
- Granted: 2013-10-29
- Earliest claimed: 2008-06-24
- Assignees: Kyushu Institute of Technology
- Applicants: Shuichi Nagamatsu; Wataru Takashima; Keiichi Kaneto
- Inventors: Shuichi Nagamatsu; Wataru Takashima; Keiichi Kaneto
- Web page: https://patentgrep.com/patent/US8569746B2

## CPC

- H10K 10/488: {the channel region comprising a layer of composite material having interpenetrating or embedded materials, e.g. a mixture of donor and acceptor moieties, that form a bulk heterojunction}
- H10K 10/466: {Lateral bottom-gate IGFETs comprising only a single gate}
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES

## Abstract

An organic field effect transistor including an organic semiconductor layer constituting a current path between a source electrode and a drain electrode wherein the organic semiconductor layer is made of a conjugated polymer having a depletion layer and a conductivity of the organic semiconductor layer is controlled by using a gate electrode, wherein the depletion layer is formed by joining a reductive material being capable of forming Schottky contact with the organic semiconductor layer made of the conjugated polymer. There can be provided an organic field effect transistor using a conjugated polymer as an organic semiconductor and being capable of maintaining an insulation property.

## Claims

### Claim 1

An organic field effect transistor comprising an organic semiconductor layer constituting a current path between a source electrode and a drain electrode wherein the organic semiconductor layer is made of a conjugated polymer having a depletion layer, and a conductivity of the organic semiconductor layer is controlled by using a gate electrode, and a gate insulation layer is disposed between the gate electrode and the organic semiconductor layer, wherein the depletion layer is formed by contacting a reductive material being capable of forming Schottky contact with the organic semiconductor layer made of the conjugated polymer, wherein the reductive material is deposited on the organic semiconductor layer with an average film thickness of 10 nm or less.

### Claim 2 (depends on 1)

The organic field effect transistor of claim 1, wherein the conjugated polymer is at least one polymer selected from the group consisting of polythiophene, polyphenylene, polyphenylenevinylene, polyfluorene, copolymers made from at least two monomers selected from the group consisting of thiophenes, phenylenes, phenylenevinylenes and fluorenes, and derivatives thereof.

### Claim 3 (depends on 1)

The organic field effect transistor of claim 1, wherein the reductive material forms a discontinuous film.

### Claim 4 (depends on 1)

The organic field effect transistor of claim 1, wherein the reductive material is a metal with a work function being at least 0.5 eV lower than an ionization potential of the conjugated polymer.

### Claim 5 (depends on 4)

The organic field effect transistor of claim 4, wherein the reductive material is aluminum.

### Claim 6 (depends on 5)

The organic field effect transistor of claim 5, wherein aluminum is deposited on the organic semiconductor layer with an average film thickness of about 2 nm.

### Claim 7 (depends on 4)

The organic field effect transistor of claim 4, wherein the reductive material is indium.

### Claim 8 (depends on 7)

The organic field effect transistor of claim 7, wherein indium is deposited on the organic semiconductor layer with an average film thickness of about 2 nm.