Enhancement of Infrared Photo-responses of the Schottky Gate Region of an n-AlGaAs/GaAs Heterojunction FET by a Second Light Illumination

摘要

Infrared (IR) photo-responses of the Schottky-barrier gate region are investigated in an n-AlGaAs/GaAs field-effect transistor (FET). The photocurrent from the channel region to the gate is strongly enhanced by about 3.4 times when a weak second light having photon energy above the GaAs bandgap illuminates the FET locally. The enhancement effect is independent of the illumination position of the second light, and remains even when the position is far away from the gate region. The experimental results are compared with a theoretical model based on the electron drift and hole diffusion.