We report measurements on the x-ray diffraction, electron spin resonance (ESR), optical absorption, and electrical conductivity of amorphous Si films. The x-ray diffraction results show there is no long-range ordering of the atoms in amorphous Si independent of the sample's thermal history, while all of the other properties show strong dependences on annealing. The ESR results indicate a large number of microscopic surfaces distributed throughout the amorphous bulk, and lead us to interpret the optical and electrical properties in terms of "building blocks" with linear dimensions between 10 and 15 Å.

• Received 6 November 1969

DOI:https://doi.org/10.1103/PhysRevB.1.2632