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Past Events
Transparent Schottky Barrier Contacts on n-GaN for Ultraviolet Detectors
| Speaker: | Mmantsae DIALE |
| Affiliation: | Department of Physics, University of Pretoria, South Africa |
| Date: | December 14, 2009 (Mon) |
| Time: | 4:00-5:00 p.m. |
| Venue: | Room 105, Chong Yuet Ming Physics Building, HKU |
Abstract:
Schottky barrier photodiodes are a choice structure for the fabrication of semiconductor UV detectors. The metal contact is expected to be transparent to incident radiation for the maximum absorption of photons. Thin metal contacts have been used, where transmission of UV light has been up to 60%. In comparison, metal oxides have given high contact transmission of up to 90%. In this work, we have explored the use of Ni/Au contact in the fabrication of Schottky barrier UV photodiodes and compared them with that of Au and Ni metals. The results show that Ni/Au contacts present low dark current and this is attributed to the formation of NiO at the metal-(Al)GaN interface. The oxide has been studied with AES, XRD and SEM. Furthermore, the electrical parameters that affect the quality of contacts were studied with I-V and C-V measurements.
Coffee and tea will be served 20 minutes prior to the seminar.