ELSEVIER Solar Energy Materials and Solar Cells 32 (1994) 213-218
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Growth of CumlTe 2 films by RF sputtering
N. Chahboun, K. El Assali, A. Khiara, E.L. Ameziane, T. Bekkay *
Laboratoire de Physique des Solides et des Couches Minces Facult~ des Sciences, Semlalia, BP S.15,
Marrakech, Morocco
(Received 10 August 1993)
Abstract
CuAITe 2 films have been grown by RF sputtering on both unheated and heated glass
substrates. The X-ray diffraction spectra exhibit one diffraction line at 24.60 ° corresponding
to the (112) direction which is the preferred orientation in the chalcopyrite phase. When
deposited onto 1500C heated substrates, the formation of binary compounds is favoured.
The resistivity variations versus the temperature show a peak around T = 140°C. In order to
study the electrical properties of p-type CuAITe 2 samples, ohmic contacts were prepared by
RF sputtering of Mo onto these films.
1.1ntroducfion
Ternary I-III-VI 2 chalcopyrite semi-conductors have received considerable
attention in recent years because of their applications in photovoltaic devices
[1-7]. It has been shown that CulnSe 2 exhibit a high conversion efficiency
(10-14%) [7-10]. However, there are extensive ranges of these compounds which
are not sufficiently explored. I-III-VI 2 thin films have been deposited using
various methods: thermal evaporation [11], sputtering [12-14], spray pyrolysis
[15-17], and electrodeposition [18-20].
The X-ray diffraction technique is usually used to characterize these films. Two
single phases are usually observed: the chalcopyrite phase and the sphalerite
phase, with preferential orientation along the (112) direction.
Several researches [21-23] have also investigated the electrical and structural
properties of CulnSe 2 and CuInS 2 thin films but there are only few studies
devoted to CuAITe z. With a band gap of the order of 2.06 eV [24], this material
* Corresponding author.
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