Micro-Raman spectroscopy studies of bulk and thin films of CuInTe_2

摘要

Micro-Raman spectroscopy measurements were made on polycrystalline and amorphous thin films of CuInTe_2 as well as bulk polycrystalline CuInTe_2. Various vibrational modes exhibited by the bulk and polycrystalline thin films were attributed to those expected for single crystal CuInTe_2. Raman spectra of amorphous films presented a broad spectrum, decomposition of which revealed the presence of elemental tellurium on the film surface. Laser-induced changes on CuInTe_2 thin films were studied by acquiring spectra with higher laser beam power. Modes due to tellurium appeared when the spectra were acquired during laser-sample interaction, indicating tellurium segregation. The Raman spectra measured from polycrystalline films during high laser power irradiation did not show decrease in the intensity of the A_1 mode of CuInTe_2 in spite of loss of tellurium from the lattice. This has been interpreted as related to an increased contribution from the undistorted subsurface CuInTe_2 region at higher excitation power.