Investigation of relative content of zinc-blende and wurtzite phases in GaP/Ge(111) using Raman spectroscopy

GaP/Ge(111) heterostructure with high residual strain is investigated for identification of allotrope, zincblende (ZB) and wurtzite (WZ) phase distribution in the grown GaP layer. Spatially resolved Raman spectroscopy across the cross-sectional surface of GaP/Ge(111) heteostructure show continuous blue shift in optical phonon frequencies from near interface to surface of GaP/Ge. Polarized Raman spectroscopy from cross-sectional surface, at near and away from interface positions, establishes that WZ phase is dominant at GaP-Ge interface. Further, higher strained regions of GaP/Ge heterostructure show larger content of wurtzite phase in GaP film. This work paves the way for probing the spatial dependent existence of allotropes and their relative content in micro/nanostructured thin films using Raman spectroscopy.