GaInAs, AlInAs Schottky barrier diodes and GaInAs/AlInAs heterojunction diode as internal photoemission detectors

The first internal photoemission detectors (IPD) of Au/GaInAs and Au/AlInAs Schottky diodes and GaInAs/AlInAs heterojunction diodes are reported. From the photoelectric measurements in the infrared band (1.1 to 2.6 µm), the best external quantum efficiency for an Au/GaInAs IPD was about 1.22% (responsivity = 19.2 mA/W) at 1.95 µm when the diode was under 0.16 V reverse bias. This quantum efficiency agrees with a calculation which suggests the optical absorptance in the metal be the major limiting factor for IPD efficiencies. The speed of IPD was also estimated with an Au/AlInAs Schottky diode to have 115 ps response rise time at 1.7 µm. Due to the conduction band discontinuity, an internal barrier exists at the GaInAs/AlInAs heterojunction interface. The heterojunction diode was fabricated as an IPD and responsivities of 0.13 mA/W to 1.37 mA/W were obtained. An internal barrier height of 0.4 eV was extrapolated.