Correlation of microstructure factor with the electronic properties of nanocrystalline silicon–germanium thin films

Abstract

The silicon–germanium (Si-Ge) binary alloy thin films are deposited in RF PECVD at different GeH4 concentrations (GC) in the plasma. The grown films are characterized by the microstructural and electronic properties. An increase in the GC reduces the Ge structure-factor as well as the Si structure-factor, as determined from the FTIR absorption studies. Simultaneously, the bonded H content (CH) in the network reduces. The studies on the electronic properties of the films reveal that an increase in the dark electrical conductivity of the films occurs with a gradual improvement in nanocrystallization in the film network. It took place via a continuous reduction in the Ge-structure factor during the increase in GeH4 concentration in the (SiH4 + GeH4 + H2) plasma.