High-performance solar-blind photodetectors based on Ta-doped ZnSnO3 single crystal thin films

Abstract

High-quality Ta-doped ZnSnO3 single crystal thin films were grown on LiTaO3 substrates by pulsed laser deposition (PLD) method, and the effects of Ta doping on the lattice structure, surface morphology, electronic structure and photodetector performance of ZnSnO3 thin films are studied in detail. When the Ta doping content is 1%, the [0001]-oriented ZnSnO3 thin film present the highest quality, which the optical band gap (3.75eV), the smoothest surface roughness (0.83nm), and the biggest carrier concentration (4.03 × 1019cm-3). For the solar-blind photodetectors (PDs), based on these excellent characteristics, the 1% Ta-doped ZnSnO3 PD exhibits large light-to-dark current ratio (>103), responsivity (21.37A/W), detectivity ((3.63±0.71) ×1011 Jones) and external quantum efficiency (~1.04× 104%) under 254nm UV light at an applied bias of 5V. This study suggests that Ta doping can effectively improve the optoelectronic performance of ZnSnO3 PDs, laying the foundation for their application.