Investigation of the carrier recombination process in undoped barium disilicide epitaxial films

Excess-carrier recombination in undoped BaSi₂ epitaxial films grown by molecular beam epitaxy on n-type silicon has been studied by the microwave-detected photoconductivity decay measurement. The measurement with various excitation laser intensities shows that dominant recombination processes change from Auger recombination to Shockley-Read-Hall recombination, and to carrier trapping with time. The numerical analysis of the Shockley-Read-Hall recombination lifetime and the X-ray rocking curve measurement of the films of 50-130 nm in thickness show that carrier capture probability has a positive correlation with the full-width at half-maximum of X-ray rocking curves, suggesting that dislocations act as recombination centers.