Layer-dependent exciton polarizability and the brightening of dark excitons in few-layer black phosphorus

Room-Temperature Self-Powered Infrared Spectrometer Based on a Single Black Phosphorus Heterojunction Diode

Infrared spectrometers with the ability to resolve the spectral intensity and wavelength simultaneously are widely used in industry and the laboratory. However, their huge volume, high price, and cryogenic operating temperature limit their applications in the rapidly developing field of portable devices. Here, we demonstrate a room-temperature self-powered infrared spectrometer based on a single black phosphorus (BP) heterojunction diode. The nonlinearly gate-tunable photocurrent spectrum involving quantum-confined Franz-Keldysh and Burstein-Moss effects in a single BP/MoS2 diode instead of using space-consuming detector arrays provides a new dimension for resolving the intensity and wavelength information of spectra simultaneously. The active area for spectral sensing is only 1500 μm2, and the photodetection range is from 1.7 to 3.6 μm. Room-temperature operation, micrometer-scale size, and silicon-compatible technology make the BP/MoS2 heterojunction a promising configuration for portable spectrometer applications.