High Performance Er-Doped ZnO (EZO)/WSe₂ Heterostructure-Based Wideband Photodetector

This article reports Al/Erbium-doped ZnO/WSe2/ITO-coated polyethylene terephthalate (PET) structure-based wideband photodetector. The EZO and WSe2 are deposited using spin coating method, whereas, Al contacts were deposited over EZO layer using thermal evaporation technique. The p-type tungsten di-selenide (WSe2) layer deposited over indium tin oxide (ITO) coated PET substrate forms a heterojunction with n-type Erbium-doped ZnO (EZO) layer. The photodetector performance parameters like responsivity, external quantum efficiency (EQE), specific detectivity, and sensitivity were calculated at fixed power of 0.118 $\mu \text{w}$ and at 2 V bias. The proposed device shows a very high EQEs/responsivity $R_{s}$ (A/W) of $2.26 \times 10^{4}$ %/72.90, $6.3 \times 10^{3}$ %/30.60, and $1.52 \times 10^{3}$ %/14.10 at 400 nm (UV), 600 nm (visible), and 1150 nm (NIR), respectively, under 2-V bias. Furthermore, the proposed photodetector behaves as a self-powered detector for normal as well as circularly polarized light (CPL). The proposed photodetector may find its application in optoelectronics for broadband detection and polarization sensors.