Effect of 80 MeV Au 8+ ions irradiation on CuInTe 2 single crystals grown by CVT technique

Abstract

Single crystals of CuInTe 2 (CIT) have been grown by the chemical vapor transport (CVT) technique using iodine as the transporting agent. CIT crystals were irradiated with 80 MeV Au 8+ ions at room temperature at different fluences. The surface roughness was measured using an atomic force microscope (AFM). It was found to increase from 9.319 nm in the as-grown sample to 61.169 nm in the sample irradiated with a fluence of 1×10 13 ions/cm 2. The intensities of the X-ray diffraction peaks corresponding to the (112) and (004/200) planes of the irradiated sample decrease with respect to the fluences. The full-width at half-maximum (FWHM) of X-ray rocking curves was measured as a function of different ion fluences. The FWHW increases with increase of ions fluences. This is attributed to the irradiation-induced partial amorphization of the top surface of the CIT crystals. The fall in absorption coefficients with photon energy is sharper for as-grown samples than irradiated samples. The band gap value gradually decreases from 1.04 to 0.977 eV upon Au 8+ ions’ irradiation with a fluence of 1×10 13 ions/cm 2. Photoluminescence (PL) measurements show a red shift compared to the as-grown CIT single crystals. The Raman modes of A 1 (high) and E and/or B 2 (LO) are observed at 123 and 173 cm −1 in as-grown CIT single crystals, respectively. As the ion fluence is increased, the Raman frequency increases and the curves broaden. The above observed features are related to the large electronic energy transfer of the Au beam to the CIT crystals.