Dark currents in GaSb/GaInAsSb heterojunction photodiodes at high temperatures

Current flow mechanisms have been studied for Liquid Phase Epitaxy (LPE) grown GaSb/GalnAsSb/GaAIAsSb heterostructures lattice-matched to GaSb substrates. The epitaxial layers have shown a good surface morphology and straight interface lines. The dark current mechanisms were investigated at several temperatures. The qualitative comparison of experimental results with theory shows that, the high temperature region the diffusion mechanism of the current flow dominates in both, forward and reverse biases. The tunneling current becomes substantial at peak junction electric fields as low as 104 V/cm due to the small direct energy gaps and small effective masses of the structure tested.