Pronounced bias-enhanced photocurrent with strong polarization sensitivity in 1T-TiSe2-based photodetectors

We report a 1T-TiSe2-based photodetector with pronounced polarization sensitivity and broadband visible-light photoresponse under low-bias conditions. Using a combined density-functional theory and nonequilibrium Green’s function approach, we calculate the transmission spectra and photocurrent under linearly polarized illumination. The photocurrent exhibits strong dependences on both photon energy and polarization angle and can be enhanced by up to two orders of magnitude under applied bias, with a concomitant increase in the extinction ratio. Analysis of the transmission spectra identifies the specific electronic transitions responsible for the photocurrent maxima. These results demonstrate an effective electrical approach to enhancing the photoresponsivity of low-dimensional photodetectors.