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Thin films of Cu2SnS3 have been deposited by the spray pyrolysis technique. Various Sn/Cu molar ratios (from 0.0 to 1.0) were applied, which allowed the study of the copper tin sulfide phase. Structural, morphological and compositional analyses have been carried out using x-ray diffraction, field emission scanning electron microscopy and energy dispersive spectroscopy. The pure CuS thin film showed the covellite phase with hexagonal crystal structure, and with increasing the Sn/Cu molar ratio, the films grown were crystallized with triclinic Cu2SnS3 ternary phase. Optical measurement analysis showed that the deposited layers have a relatively high absorption coefficient (∼105 cm−1) in the visible spectrum, about one order of magnitude higher than in other published reports. Also these layers presented a reduction of about 1 eV in the values of band gap from 2.57 to 1.58 eV with an increment in the Sn/Cu molar ratio from 0.0 to 1.0. The electrical properties studies showed that all these samples are p-type semiconductors and the resistivity decreases with increasing the Sn/Cu molar ratio.

The transport properties of Mg-doped, p-type GaN films grown by MOCVD have been measured using Hall effect and resistivity measurements over a temperature range of 400-120 K. The mobility is found to increase slowly over the temperature range of 400-150 K. Below this temperature the mobility is seen to decrease rapidly, while the corresponding Hall carrier density goes through a minimum before increasing to lower temperatures. These results have been analysed, using a two-band model. This incorporates a simple valence band model, calculated using a relaxation time approximation, and additional transport within an acceptor impurity band. A good fit has been obtained selfconsistently to both the mobility and carrier density over a temperature range of 400-120 K. We find that neutral scattering plays an important role in limiting the hole mobility.

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