Structural changes induced by nitrogen in the a-Ge:H network

R.R. CAMPOMANES; D. COMEDI; I. CHAMBOULEYRON

JOURNAL OF APPLIED PHYSICS

Año: 1999 vol. 85 p. 3108 - 3113

0021-8979

The structural modifications induced by the incorporation of nitrogen (2 at.%< CN < 6 at. %, CN = N concentration) in radio frequency-sputtered hydrogenated amorphous germanium (a-Ge:H) has been studied by infrared spectroscopy. At all N concentrations there is a substantial increase of the density of voids, as indicated by the strength of the absorption band associated with the surface-like stretching vibration of the Ge–H dipole. As CN increases, the peak position of this mode shifts to smaller values. These effects are also detected through the analysis of the wagging vibration modes of the Ge–H dipole. Comparison of the present results with similar data for H-free a:GeN indicates that the presence of H in the reaction hinders the incorporation of the NGe3 skeletal group, characteristic of b-Ge3N4. The overall data indicate that almost all N incorporates in N–H and N–H2 configurations, which are responsible for the formation of a large quantity of small-size voids.