Ultraviolet photodetectors based on Si-Zn-SnO thin film transistors with a stacked channel structure and a patterned NiO capping layer

Ultraviolet photodetectors (UVPDs) based on Si-Zn-SnO (SZTO) thin-film transistors (TFTs) with a stacked dual-channel layer (DCL) structure with different carrier concentration and NiO capping layer (CL) to alleviate the trade-off between dark current (I _dark) and photocurrent (I _ph) are reported. Experimental results show that under 275 nm irradiation, the proposed SZTO TFT UVPD with a 30 nm thick upper layer stacked on a 50 nm thick channel layer and a patterned NiO CL exhibit excellent photoresponsivity and photosensitivity up to 1672 A W⁻¹ and 1.03 × 10⁷ A A⁻¹, which is about 272 and 137 times higher than conventional 30 nm thick single-channel layer SZTO TFT.