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Pt/AlGaN Metal Semiconductor Ultra-Violet Photodiodes on Crack-Free AlGaN Layers

2003; Institute of Physics; Volume: 42; Issue: Part 1, No. 4B Linguagem: Inglês

10.1143/jjap.42.2349

1347-4065

Young‐Ro Jung, Jae‐Hoon Lee, Jung-Kyu Kim, Young‐Hyun Lee, Myoung‐Bok Lee, Jung-Hee Lee, Sung‐Ho Hahm,

ZnO doping and properties

Schotty-type solar-blind ultra-violet photodetectors were designed and fabricated by employing an unintentionally doped AlGaN layer, grown on a sapphire substrate by metal-organic chemical vapor deposition (MOCVD). When a low-temperature grown AlGaN interlayer was inserted between the GaN and AlGaN active layers, it was found to play an important role in decreasing the thermal and lattice mismatch-induced crack density in the active AlGaN layer. The Schottky-type photodetectors fabricated on the crack-free AlGaN layer then exhibited excellent electrical characteristics and UV sensing behavior. Accordingly, the resulting Pt/AlGaN metal semiconductor photodiode had a dark current of 9 nA at -5 V, cut-off wavelength of 310 nm, and quantum efficiency of 65% at 280 nm, plus the UV/visible extinction ratio was ∼104 in the band edge, which is one of the highest values recorded for an AlGaN photodetector.