Electrically Modulated Wavelength-Selective Photodetection Enabled by <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><mml:msub><mml:mrow><mml:mi>Mo</mml:mi><mml:mi mathvariant="normal">S</mml:mi></mml:mrow><mml:mn>2</mml:mn></mml:msub><mml:mo>/</mml:mo><mml:mrow><mml:mi>Zn</mml:mi><mml:mi mathvariant="normal">O</mml:mi></mml:mrow></mml:math> Heterostructure
Kishan Kumawat, Pius Augustine, Deependra Kumar Singh, Karuna Kar Nanda, S. B. Krupanidhi
Abstract
Regardless of the significant progress in photodetectors (PDs), most conventional technologies are equipped with optical filters for spectral discrimination, which results in expensive circuitry as well as a high incidence of energy loss. Different from traditional PDs, a ${\mathrm{Mo}\mathrm{S}}_{2}/\mathrm{Zn}\mathrm{O}$ heterostructure-based PD is demonstrated that exhibits a bias-dependent switchable spectral response. A low-band-gap ${\mathrm{Mo}\mathrm{S}}_{2}$ thin film is vertically stacked on top of a high-band-gap $\mathrm{Zn}\mathrm{O}$ film that allows selective charge transport from each layer by modulating the applied bias, resulting in a fine discrimination between visible and near-infrared (NIR) light. Under a lower applied bias, a dominant photoresponse in the visible region by the $\mathrm{Zn}\mathrm{O}$ film is observed, whereas an enhanced response in the NIR region is obtained at higher bias, which is attributed to the generation of charge carriers in the ${\mathrm{Mo}\mathrm{S}}_{2}$ region. The excellent figures of merit obtained in the study attest to the high quality of the device, paving the way for fabricating energy-efficient imaging systems free of optical filters.