2024/11/10 by Luo, Yuezhou, Flewitt, Andrew John
#Applied Physics (physics.app-ph) #Disordered Systems and Neural Networks (cond-mat.dis-nn) #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci)
paper · doi:10.48550/arxiv.2411.06439
Amorphous semiconductors are important channel semiconductors in thin film transistors (TFTs) which serve not only active-matrix displays, but also flexible electronics for Internet of Things (IoT) applications. Nevertheless, a great limitation of amorphous semiconductors is their low carrier mobilities relative to their monocrystalline counterparts. Based on a recently established band fluctuation framework [Y. Luo and A. Flewitt, Phys. Rev. B 109, 104203 (2024)], this paper shows that the intrinsic carrier mobility of amorphous semiconductors can significantly increase simply through device downscaling, without any material-level optimizations. Specifically, it is revealed that the intrinsic electron mobility of hydrogenated amorphous silicon in a 10-nm long gap can increase by around 12 times, and does not compromise device-to-device uniformity. This mobility improvement is a result of reduced localized band tail states due to the ultra-short gap length relative to the band fluctuation length scale before downscaling; the latter is determined by the short- and medium-range structural order of the amorphous semiconductor.