Patent ID: 8748872

Claim:
An organic transistor comprising: a conductive element which forms a drain; a conductive element which forms a source located away from the drain; a conductive element which forms a gate having a surface which faces the drain and a surface which faces the source; a semiconducting layer which is in contact with the drain and the source so as to produce a charge-carrier channel between the drain and the source; a dielectric layer covering the semiconducting layer, the dielectric layer comprising a first dielectric material having a dielectric permittivity of less than four and a volume of second dielectric material having a dielectric permittivity of greater than four, wherein the dielectric layer comprises three locational portions, a first portion located between opposite facing surfaces of the gate and the source, and a second portion located between opposite facing surfaces of the gate and the charge carrier channel, and a third portion located between opposite facing surfaces of the gate and the drain; and wherein said volume of second dielectric material has an overall cross-section which tapers from the gate towards the charge-carrier channel, and wherein said first portion of said dielectric layer and said third portion of said dielectric layer consist essentially of the first dielectric material, and wherein said second portion of said dielectric material consists essentially of the second dielectric material.