Salt‐Assisted Low‐Temperature Growth of 2D Bi<sub>2</sub>O<sub>2</sub>Se with Controlled Thickness for Electronics
Usman Khan, Adeela Nairan, Karim Khan, Sean Li, Bilu Liu, Junkuo Gao
Abstract
Abstract Bi 2 O 2 Se is the most promising 2D material due to its semiconducting feature and high mobility, making it propitious channel material for high‐performance electronics that demands highly crystalline Bi 2 O 2 Se at low‐growth temperature. Here, a low‐temperature salt‐assisted chemical vapor deposition approach for growing single‐domain Bi 2 O 2 Se on a millimeter scale with thicknesses of multilayer to monolayer is presented. Because of the advantage of thickness‐dependent growth, systematical scrutiny of layer‐dependent Raman spectroscopy of Bi 2 O 2 Se from monolayer to bulk is investigated, revealing a redshift of the A 1g mode at 162.4 cm −1 . Moreover, the long‐term environmental stability of ≈2.4 nm thick Bi 2 O 2 Se is confirmed after exposing the sample for 1.5 years to air. The backgated field effect transistor (FET) based on a few‐layered Bi 2 O 2 Se flake represents decent carrier mobility (≈287 cm 2 V −1 s −1 ) and an ON/OFF ratio of up to 10 7 . This report indicates a technique to grow large‐domain thickness controlled Bi 2 O 2 Se single crystals for electronics.