An investigation of structural and electrical properties of boron doped and undoped nanocrystalline diamond films

Abstract

Nanocrystalline and microcrystalline undoped and boron doped diamond films are investigated by means of SEM, Raman and photocurrent techniques. SEM measurements on nanocrystalline diamond show the typical diamond columnar structure whereas for microcrystalline diamond such structure is not observed. Raman investigation shows a clear diamond peak at 1332 cm(-1) for all investigated films and a Fano resonance is observed for the microcrystalline sample prepared with 2000 ppm of boron in the gas mixture indicating a transition into the semi-metallic state. Photocurrent measurements also show a presence of boron in some films. It is found that when temperature is decreased lower than 80 K, the boron photocurrent threshold in the case of NCD material behaves differently compared to bulk diamond.