Liquid‐Alloy‐Assisted Growth of 2D Ternary Ga2In4S9 toward High‐Performance UV Photodetection

Abstract

2D ternary systems provide another degree of freedom of tuning physical properties through stoichiometry variation. However, the controllable growth of 2D ternary materials remains a huge challenge that hinders their practical applications. Here, for the first time, by using a gallium/indium liquid alloy as the precursor, the synthesis of high-quality 2D ternary Ga2 In4 S9 flakes of only a few atomic layers thick (≈2.4 nm for the thinnest samples) through chemical vapor deposition is realized. Their UV-light-sensing applications are explored systematically. Photodetectors based on the Ga2 In4 S9 flakes display outstanding UV detection ability (R λ = 111.9 A W-1 , external quantum efficiency = 3.85 × 104 %, and D* = 2.25 × 1011 Jones@360 nm) with a fast response speed (τring ≈ 40 ms and τdecay ≈ 50 ms). In addition, Ga2 In4 S9 -based phototransistors exhibit a responsivity of ≈104 A W-1 @360 nm above the critical back-gate bias of ≈0 V. The use of the liquid alloy for synthesizing ultrathin 2D Ga2 In4 S9 nanostructures may offer great opportunities for designing novel 2D optoelectronic materials to achieve optimal device performance.