Tellurium/GaAs heterojunctions fabricated by thermal evaporation in vacuum

Heterostructures containing thin tellurium layers thermally evaporated on differently doped GaAs substrates were systematically investigated by using THz pulse excitation spectroscopy. The observed differences of the THz excitation spectra were explained by the details of the energy band lineups in the heterostructures. Comparison of the simulation results of the heterojunction between tellurium and semi-insulating GaAs with the measured THz pulse emission spectrum allowed one to estimate the electron affinity in the tellurium layer. In addition, a near-infrared photodetector based on the Te heterojunction with n-type GaAs was demonstrated.