This paper reports the optical properties of the photovoltaic material CuInTe2 (CIT) as characterized by photoacoustic spectroscopy (PAS), who yields direct information on non-radiative absorption processes which are usually associated with the band structure and defect-related energy loss mechanisms.
Measured spectra of p-conducting CIT single crystals are given using a high resolution near infrared photoacoustic spectrometer of the gas-microphone type. The data is used to evaluate the absorption spectra, the band gap energy, and ionization energies of defects that have been observed in the tail of the spectra (1).
Ionisation energies of intrinsic defects are derived from the appropriately determined values of the gap energy. Different energy levels have been observed. The sallow level assigned to the antisite defect CuIn and two levels were assigned to the vacancies of Cu(VCu) and Te(VTe). The PAS technique reveal the presence of populations of deep defects in our samples (3).
The obtained results confirm the efficiency of the technique in detecting the non-radiative defects known to dominate the properties of this compound. A discussion on the relation between the composition of the samples and the intrinsic defect chemistry in this compound is also given. Finally, we give a comparison between the results we have obtained and those published in the literature (3, 4).
1)A.Zegadi, A. Boloufa, N. Mazouz, B. Barka, E. Ahmed, A. E. Hill and R. D. Tomlinson. PV in Europ. Photovolt. Sol. Energy Conf., Rome 11-17 Oct. Italy, 81 (2002)
2)A. Zegadi, M.A. Slifkin, M. Djamin, R. D. Tomlinson and H. Neumann, Sol. Stat. Commun. 83, 591 (1992)
3)M. V. Yakushev, H. Neumann and R.D.Tomlinson, Cryst. Res. Technol. 30, 121(1995)
4)A.Zegadi, A. Bouloufa, M. Rouha, A. Messous M. V. Yakushev and R. D. Tomlinson. 17th Europ. Photovolt. Sol. Energy Conf., Munich 22-26 Oct. Germany, 1062 (2001)