Local order as determined by electronic and vibrational spectroscopy: Amorphous semiconductors

Abstract

Raman and infrared spectroscopy yield detailed information about the vibrational modes of solids. Photoelectron spectroscopy gives corresponding information on valence and core electronic states. From these spectroscopies the nature of the local atomic order can be inferred. Applications of these methods are illustrated for prototype tetrahedral and chalcogenide amorphous semiconductors. The retention of the crystalline short range order is manifested in the vibrational spectrum of pure amorphous silicon and the III-V compounds. Similar conclusions are obtained from the photoelectron spectra along with additional information on ring configurations. For Se and chalcogenide compounds (e.g. GeTe) vibronic and electronic spectral reveal differences between amorphous and crystalline short range orders. In addition to these intrinsic structures, the local environments and effects of additives, such as hydrogen and conventional dopants in amorphous silicon, are discussed. © 1978.