Ni/GaN Schottky diode radiation detectors were fabricated on 3-μm -thick unintentionally doped n-GaN films grown by molecular beam epitaxy (MBE) and metal organic chemical vapor deposition (MOCVD) and on 12-μm -thick undoped n-GaN layers prepared by epitaxial lateral overgrowth (ELOG). The reverse current of all detector structures was < 10-9 A for bias voltages necessary for detector operation, with the level of background donor doping of < 1015 cm-3With this doping level the space charge region of the Schottky diode could be extended to the entire thickness of the films. The charge collection efficiency of the detectors was close to 100% for MOCVD and ELOG detectors for α -particles with range comparable to the thickness of the layer. Electrical properties and deep trap spectra were also studied. The collection efficiency decreased when the concentra-tion of deep electron traps, particularly Ec-0.6 eV traps, increased in MBE grown films.
ASJC Scopus subject areas
- Physics and Astronomy(all)