Physica B 337 (2003) 369–374 Photoluminescence studies of heavily doped CuInTe 2 crystals A. Jagom . agi a, *, J. Krustok a , J. Raudoja a , M. Grossberg a , M. Danilson a , M. Yakushev b a Department of Materials Science, Tallinn Technical University, Ehitajate tee 5, Tallinn 19086, Estonia b Department of Physics and Applied Physics, 107 Rottenrow, Strathclyde University, Glasgow G40NG, UK Received 7 May 2003; received in revised form 2 June 2003; accepted 22 June 2003 Abstract The photoluminescence spectra of heavily doped CuInTe 2 and their dependence on the temperature and excitation power were measured. At 10K an asymmetric broad peak at 0.98eV was observed. The PL peak position did not depend on the excitation power, but had a characteristic dependence on the sample temperature. Our computer simulations proved that this behaviour is in good compliance with the Shklovskij/Efros model of heavily doped semiconductors with spatially varying potential fluctuations. Therefore, the PL band was attributed to the band-to- impurity type recombination and the corresponding level to the single acceptor at 70meV, which is most probably caused by copper vacancy. r 2003 Elsevier B.V. All rights reserved. PACS: 78.55.Hx; 71.55.Ht; 61.72.Ji Keywords: Photoluminescence; Chalcopyrite ternary crystals; CuInTe 2 ; Point defects 1. Introduction CuInTe 2 (CIT) is a direct band gap chalcopyrite ternary semiconductor that has the energy gap in the vicinity of 1eV, being very close to the optimum for solar energy conversion. This makes CIT attractive for solar cell applications. Photoluminescence (PL) is a very effective and a relatively easy-to-use tool for studying the defect structure of semiconductors. The advantage is its high sensitivity to small changes in the compound structure. Nevertheless, it is not the ultimate tool because some defect states that do not give radiative recombination remain undetected. More- over,abroadandindistinctexperimentalspectrum can sometimes be very tedious to interpret. Yet, using an adequate theoretical model, many char- acteristic phenomena of PL spectra can be explained. PL measurements have been conducted on CIT by Rinc ! on et al. [1,2]. They report the excitonic and edge emission that refer to relatively regular crystals. This paper describes the experimental PL spectra of heavily doped CuInTe 2 crystals. By heavily doped we mean crystals that have a large concentration of intrinsic defects rather then a high concentration of impurity atoms. In fact, CIT ARTICLE IN PRESS *Corresponding author. Tel.: +372-620-3210; fax: +372- 620-2798. E-mail address: andri@kiri.ee (A. Jagom. agi). 0921-4526/$-see front matter r 2003 Elsevier B.V. All rights reserved. doi:10.1016/S0921-4526(03)00429-0