Fast-response self-powered double-heterojunction n-ZnO/p-ZnTe/n-Si photodetector

This study elucidates a novel, fast-response, self-driven double-heterojunction (n-ZnO/p-ZnTe/n-Si) photodetector fabricated <i>via</i> the rapid pulsed laser deposition (PLD) technique. The proposed geometry exhibits dual-responsive behavior under ultraviolet (375 nm) and visible (530 nm) incident wavelengths due to the heterojunctions (n-ZnO/p-ZnTe/Si and p-ZnTe/n-Si). Under a 0.5 bias condition, the former exhibited photo-responsivity (<i>R</i> _λ) and photo-detectivity (<i>D</i>*) of 64.03 mA W^-1 and 5.19 × 10¹⁴ Jones at 375 nm, while the latter demonstrated values of 53.20 mA W^-1 and 2.44 × 10¹⁴ Jones at 530 nm, respectively; lower figure-of-merits were observed at higher and/or lower wavelengths. However, a higher applied bias contributes to a significant <i>R</i> _λ and <i>D</i>* augmentation under these wavelengths. The observed characteristics were found to decrease at high incident light intensity, which suggests a negative correlation between the calculated parameters, with an <i>R</i> ² value close to unity (<i>R</i> ² = -1). At zero applied bias, the proposed system demonstrated a stable performance over a period of 5 days with less than 1.5% variation. The response/recovery times for the proposed heterojunctions were 88/90 ms and 89/94 ms under 375 nm and 530 nm, respectively.