The Effect of a Copolymer Interfacial Layer on the Performance of Organic Thin-Film Transistors

Abstract

The effects of adding a copolymer interfacial layer on the performance of Poly (3-hexylthiophene-2, 5-diyl) (P3HT) based organic thin-film transistors (OTFT) were investigated. Poly (oligo (ethylene glycol) methyl ether methacrylate- glycidyl methacrylate- lauryl methacrylate), which is referred to as POGL, was used as an interfacial layer between P3HT and the dielectric. OTFTs with and without a POGL interfacial layer were fabricated. The field-effect mobility and the threshold voltage were extracted for all the devices. The OTFTs with a POGL interfacial layer were observed to have a smaller threshold voltage than the OTFTs without an interfacial layer, which makes the POGL devices attractive for low power applications. The POGL OTFTs were also observed to have much more ideal drain current saturation characteristics with very small I-V curve slope. This is explained by the deep trap states on the POGL surface and the reduction of the contact resistance at the electrode/organic semiconductor interface. However, the POGL OTFTs were observed to have a smaller drain current and a slightly smaller mobility than the non-POGL OTFTs. This is explained by the surface roughness of the POGL, which affects the charge transport in the channel of the device.

Growth of CuAlO2 on SiO2 under a layer-by-layer approach conducted by digitally processed DC sputtering and its transistor characteristics

“…The CAO TFT's threshold voltage (V th ) is an important parameter determined by a horizontal axis intercept of a linear extrapolation of the transfer curve. 31,32) V th for the highly oriented and as-deposited CAO TFT were −7.53 V and −9.0 V, respectively. In annealing, the thermal energy facilitates the healing of crystal defects, which minimizes the hole traps at the CAO/SiO 2 interface, 33) consequently reducing the V th in the higher annealing CAO TFT.…”