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