III-Nitride Schottky Rectifiers With an AlGaN/GaN/AlGaN/GaN Quadruple Layer and Their Applications to UV Detection

III-nitride Schottky rectifiers (SRs) with (i.e., SR_A) and without (i.e., SR_B) the AlGaN/GaN/AlGaN/GaN quadruple layer were both fabricated. It was found that we could achieve a lower leakage current from SR_A. Under reverse bias, it was found that SR_A showed a more than five orders magnitude smaller dark current than that in SR_B. It was also found that lower on-state resistance was due to the larger Schottky barrier height and larger breakdown voltage was due to reduced defect densities in SR_A. The SRs with a quadruple layer was suitable for applications to low noise or/and ultraviolet (UV) detection as well.