Optical and electrical properties of amorphous and microcrystalline GaN films and their application to transparent TFT

Amorphous and microcrystalline GaN thin films have been made by reactive sputtering. The dark conductivity can be changed largely from 10(-11) S/cm of amorphous GaN to 10(-3) S/cm of microcrystalline GaN with a crystalline size of 700 Angstrom. Photoconductivity and persistent photoconductivity (PPC) are observed above room temperature in these films. And a thin film transistor (TFT) was made by using GaN film and observed the operation as a TFT.