Westfälische Wilhelms-Universität Münster
- Fachbereich Physik -
KOLLOQUIUM ÜBER SPEZIELLE
FRAGEN DER PHYSIK
Montag, 17. Juni 2002
Prof. Dr. Joshua Halpern
Department of Chemistry, Howard University Washington
Growth of Wide Bandgap GaN Nanowires and Construction of a Simple GaN UV Phototransistor
We have recently discovered a simple, catalyst free method of growing single crystal GaN fibers with diameters ranging from 15 nm to 20 mm. These structures are quite long, some approaching a millimeter in length. The wurzite fibers are grown by reaction of Ga metal vapor with ammonia in a tube furnace between 800 and 1000ºC under Ga rich conditions. They grow along well defined crystal axes starting from the edges of small GaN platelets. We have constructed simple transistor devices from some of these fibers which have been found to be n-type semiconducting. A large increase in current was observed when the transistor was illuminated with UV light but not with visible light. The experimental results, fiber growth mechanism and device fabrication will be described in detail. Future directions for this research will be discussed.
Ort: Wilhelm-Klemm-Str.
9, Hörsaal 404
Zeit: 17
Uhr c.t.
Einladender:
Zacharias