Investigations of surface roughness of GaN based gas sensor using atomic force microscope

In this paper, the properties of GaN based gas sensor with different thickness of platinum (Pt), prepared by sputtering method and annealed in air at 600/spl deg/C were investigated. AFM micrography showed that the GaN and Pt films are grain-like, and the grain size increases after annealing upon gas exposure. The interaction between the Pt clusters and the GaN grains was investigated. Sensors fabricated with the Pt films exhibited a significant increase in their sensitivity and selectivity towards H/sub 2/ detection when the thickness of Pt films is increased. Changes in the surface roughness for the different thickness of Pt/GaN due to specific adsorptions are presented. Possible applications and improvements of this technique are discussed.