Homojunction Interface Boosts Hole-Carrier Injection in p-Type CuI Nanoribbon Field-Effect Transistors

Abstract

Despite substantial advancements in n-type 1D and 2D nanostructures, achieving p-type field-effect transistors (FETs) using 1D nanostructures remains a formidable challenge due to surface defects and doping limitations. This study presents a scalable approach for fabricating the p-type homojunction (p/p+) CuI nanoribbons (CuI NRs) with enhanced charge injection. Characterization of iodide-exposed (I-rich) CuI thin films reveals improved crystallinity and significantly higher carrier concentration compared with pristine CuI thin films. Leveraging the unique carrier tuning property of CuI, localized iodine exposure facilitated by electron beam lithography at the source/drain electrode interface of CuI NRs leads to the formation of a homojunction CuI NR. The homojunction CuI NR p-type FETs exhibits performance improvements, with three-orders of magnitude lower contact resistance and high mobility (5.6 cm2V-1s-1) with an on/off ratio of 104. Temperature-dependent studies reveal the presence of shallow traps and a reduced Schottky barrier height in the homojunction CuI NR FETs, contributing to efficient charge transfer at the metal-semiconductor interface. These findings establish CuI NR as a promising material for developing reliable p-type semiconductor devices. The fabrication of homojunction CuI NRs represents a significant advancement in the field of 1D nanostructures, holding immense potential for cost-effective and scalable device fabrication.