p-type ZnTe:Ga nanowires: controlled doping and optoelectronic device application

Abstract

Although significant progress has been achieved in the synthesis and doping of ZnTe nanostructures, it remains a major challenge to rationally tune their transport properties for nanodevice applications. In this work, p-type ZnTe nanowires (NWs) with tunable conductivity were synthesized by employing Ga/Ga₂O₃ as a dopant via a simple thermal evaporation method. Electrical measurements of back-gate metal-oxide field-effect-transistors based on a single NW revealed that when the Ga content in the ZnTe NWs increases from 1.3 to 5.1 and 8.7%, the hole mobility and hole concentration will increase from 0.0069 to 0.33 to 0.46 cm² V⁻¹ s⁻¹, respectively. It was also found that the photodetector composed of a ZnTe:Ga NW/graphene Schottky diode exhibited high sensitivity to visible light illumination with an on/off ratio as high as 10² at reverse bias, with good reproducibility. The responsivity and detectivity were estimated to be 4.17 × 10³ A W⁻¹ and 3.19 × 10¹³ cm Hz^1/2 W⁻¹, higher than other ZnTe nanostructure based photodetectors. It is expected that the ZnTe:Ga NWs with controlled p-type conductivity are promising building blocks for fabricating high performance nano-optoelectronic devices in the future.