Wavelength conversion in a Schottky diode

Summary form only given. We report a method of up-converting radiation from 1.5 /spl mu/m to 818 nm, based on internal photoemission. This involves the photoexcitation of carriers across a metal-semiconductor interface and subsequent recombination in a p-doped quantum well. Near-infrared light of wavelength 1.5 /spl mu/m is directed upon the surface of a metal in contact with a p-type modulation doped GaAs/AlGaAs quantum well. This results in the excitation of electrons in the metal. In the absence of external bias band-bending at the Schottky interface keeps photoexcited electrons from reaching the quantum well. However, if a forward bias is applied between the Schottky contact and the hole-gas channel, the Fermi level at the metal-semiconductor interface is raised and the direction of the band bending is reversed. Under such conditions, electrons photoexcited with an energy slightly lower than the Schottky barrier height tunnel into the semiconductor where they drift towards the quantum well. The electrons are captured in the quantum well where they recombine radiatively, resulting in luminescence at an energy corresponding to the lowest electron-hole transition of the quantum well. This emitted light has greater energy than the energy of the incident photons that lift electrons across the Schottky barrier, therefore up-conversion of near-infrared to visible light occurs.