Phase-defined growth of In2Se3 thin films using PLD technique for high performance self-powered UV photodetector

Abstract

Self-powered photodetectors have attracted enormous attention for their high sensitivity, fast response with low power consumption. The unique set properties defined for various polymorphs of In2Se3 offers wide range of potential applications for optoelectronic and memory devices. Here, threephases of In2Se3 including, layered α-In2Se3and β-In2Se3, and non-layered γ-In2Se3, are grown using pulsed laser deposition (PLD) technique. Deposition gas pressure is found to govern the formation ofIn2Se3phasesattributed to flux of Se atoms reaching the heated substrate. Band structure, density of states and work function for each phase iscalculated using first principles calculations to understand their electronic properties. Based on the obtained work functions, it is found that Schottky junction based ultraviolet photodetectors usingas grownIn2Se3 films exhibit high performance with photo-responsivity of1310 mA/W for α-In2Se3, 260 mA/W for β-In2Se3and 240 mA/W for γ-In2Se3 in self-poweredmode under an illumination of ultraviolet radiation. The obtained high self-powered photodetectionis attributed to the non-centrosymmetric structure of α-In2Se3and γ-In2Se3, which produce a built-in field due to in-plane spontaneous polarization. Thus, In2Se3based self-powered photodetector prepared using PLD technique pave the way forlow power optoelectronic device applications, environmental monitoring and military applications.