Growth of CuGaTe₂ based compounds by a closed space sublimation method

Chalcopyrite I-III-VI₂ compounds are considered as novel potential materials for solar cells. Among the variety of those compounds, CuGaTe₂ and AgAlTe₂ films were grown by a closed space sublimation method. Crystallinity and stoichiometry of grown films were evaluated by X-ray diffraction measurements. When CuGaTe₂ powder source was used to grow CuGaTe₂ films at around 840 °C of the source temperature, stoichiometric CuGaTe₂could not be formed. X-ray diffraction measurements revealed that the deposited material was Cu-Ga compound. The desorption of Te was compensated by adding elemental Te in the source material. These stoichiometric CuGaTe₂ films were achieved when the volume of additional Te was around twice weight of CuGaTe₂. On the other hand, growth of AgAlTe₂ films could be achieved when the source temperature was 800 °C, and no additional Te was introduced in the source. From X-ray diffraction measurements, it was found that these two compounds films had strong preference for the (112) orientation on the quartz substrate.