Phototunnel conductance effect in GaAs p‐n and MIS junctions

摘要

p‐n tunnel junctions made by alloying and MIS tunnel junctions made by contacting the metal were fabricated using degenerate n‐type GaAs substrates. The conductance G and capacitance C of these diodes have large sensitivity to light irradiation and show similar spectra with respect to photon energy. The relative variation of photoconductance with initial dark conductance, ΔG/Gd, is more than ten times that of the photocapacitance, ΔC/Cd. It was found that the quenching light effect is observed in p‐n tunnel junctions but not in MIS tunnel junctions. These phenomena are explained by considering the change of trapped charge in the deep level due to illumination which induces a change of the depletion layer structure and the tunneling probability, resulting in the changes of C and G (phototunnel conductance). The experimental results have been shown to agree well with theoretical calculations.