Bimodal multilayer nanostructure based on vanadium dioxide phase transition: absorber and hot electron photodetector

Recently, interest in the use of hot electron photodetectors (HEPDs) for energy harvesting has increased. In this paper, we introduce a switchable structure consisting of an absorber and metal/semiconductor Schottky-junction HEPD that incorporates a phase change material in the design. The structure is a purely planer configuration composed of a vanadium dioxide (VO2)/molybdenum disulfide (MoS2)/photonic crystal-distributed Bragg reflector (PC-DBR). VO2 is a phase change material that exhibits a reversible semiconductor to metal phase transition at the critical temperature of 68 degrees C. The nanostructure response relies on the VO2 phase transition under thermal heating. The transition of the VO2 phase from the semiconductor to the metal phase causes the formation of the Schottky-junction between the VO2/MoS2 interface, causing the structure to switch from the absorber to the hot electron photodetector in the near infrared region. In addition to, the switchable absorber-HEPD response; the absorption-photoresponsivity shows spectral tunability via the chosen thickness of the VO2 and MoS2 layers. This hybrid nanostructure is also sensitive to the light polarization state of both TE and TM modes. The proposed hybrid nanostructure is a promising candidate for switchable absorber-HEPD structures, with applications as switchable hot electron-based photovoltaic and sensing systems.