Hu Weida

High-mobility transparent amorphous metal oxide/nanostructure composite thin film transistors with enhanced-current paths for potential high-speed flexible electronics

We review the improved performance of amorphous oxide semiconductor (AOS) based thin film transistors (TFTs) with embedded nanostructures. Amorphous indium zinc oxide/single-walled carbon nanotube (a-IZO/SWNT) composite TFTs exhibited a high mobility of 140 cm2 V−1 s−1 and robust flexibility comparable with those of organic TFTs. Obtaining the optimal device operation performance depends critically on the full control of mobility and threshold voltage (Vth). The Vth was readily tuned to a favourable value, and the device maintained a reasonably high mobility of 132 cm2 V−1 s−1. Moreover, the intrinsic cut-off frequency fT could reach 72 MHz. The amorphous indium zinc/In2O3 nanocrystalline (a-IZO/In2O3 NC) composite TFTs also demonstrated that the enhanced-current paths could generally improve the mobility of the AOS TFTs. The proposed strategy was reliable and reproducible for large-scale fabrication. The overall high performance indicated that amorphous metal oxide/nanostructure composite TFTs were readily suitable for large-scale low-power radio frequency applications.

Influence of hydrogenation on the dark current mechanism of HgCdTe photovoltaic detectors

The influence of hydrogenation on the dark current mechanism of HgCdTe photovoltaic detectors is studied. The hydrogenation is achieved by exposing samples to a H2/Ar plasma atmosphere that was produced during a reactive ion etching process. A set of variable-area photomask was specially designed to evaluate the hydrogenation effect. It was found that the current–voltage characteristics were gradually improved when detectors were hydrogenated by different areas. The fitting results of experimental results at reverse bias conditions sustained that the improvement of current–voltage curves was due to the suppression of trap assisted tunneling current and the enhancement of minority lifetime in the depletion region. It was also found that the dominative forward current was gradually converted from a generation–recombination current to a diffusion current with the enlargement of the hydrogenation area, which was infered from the ideality factors by abstraction of forward resistance–voltage curves of different detectors.