X-RAY DIFFRACTION STUDY OF ATOMIC STRUCTURE OF PLASMA DEPOSITED a-Si:H ALLOYS

Abstract

The atomic structure and defects have been studied by measurements of the x-ray diffraction, density, infrared spectra and optical absorption in a series of plasma-deposited a-Si : H alloys prepared by glow-discharge decomposition of silane (GD) and reactive sputtering of Si target (SP). The first peak of x-ray diffraction intensity shows the systematic changes in position and intensity with increasing H concentration CH. The first coordination number of Si atoms in GD a-Si : H decreases to 3.7±0.1 with increasing CH to 20 at.% while in SP a-Si : H it decreases more rapidly 3.3±0.1. The first coordination distance in these alloys remains unchanged. The systematic change in the structural data with CH are discussed in connection with bonding conformation and defects.