High-performance transparent and broadband p-Co3O4/n-SnO2 photodetectors

Abstract

This work demonstrates cost-effective fabrication of SnO₂/Co₃O₄ thin films heterostructure-based p-n junction type transparent and broadband photodetectors (PDs) with substantially high figures of merit. Herein, the effects of order of stacking layers and thickness of top layer material on the transparency and photodetection performance of devices are investigated. The observed transparency (≥ 65 % beyond 380 nm) along with dark and photoconductivity depend on both the order of stacking layers and the thickness of the layers, which are explained on the basis of the bandgap of materials and interface scattering centers. The present study demonstrates that PDs performance can be tailored by an order of two by controlling these two parameters. The proposed p-n heterojunction PDs exhibit high sensitivity, responsivity, detectivity, and external quantum efficiency of the order of 10²-10⁵%, ∼10¹-10³ A/W, ∼ 10¹¹-10¹⁴ Jones, and 10³-10⁶%, respectively, in the broad (UV-Vis-NIR) spectral region. Remarkably, the sustainability in the performance of PDs under the illumination of visible and NIR lights with respect to the performance under UV light illumination is much better than previously designed PDs. The highest performance parameters were observed for device C₁₅S₁₀ under the broadband spectrum (365 nm–845 nm), with a maximum value under 365 nm illumination and an average response speed of ∼225 ms.