Large grain size CdTe films grown on glass substrates

Polycrystalline films of CdTe (with grain size up to 100 μm) were grown by the hot wall close-spaced vapor transport technique in an Ar atmosphere. In most cases they grow on a zinc-blende type of structure with a preferential orientation of growth along the 〈111〉 directions, as shown by x-ray diffraction studies. The grain size in the films presents a maximum around 3.5 Torr, as well as a minimum of preferential orientation. The grain size shows an exponential increase in the substrate temperature (Ts) 450–650 °C range. For Ts≤600 °C, the films grow with a 〈111〉 preferential crystallographic orientation, whereas for Ts>600 °C the preferential orientation changes to the 〈220〉 directions. For Ts>600 °C, the films show a mixture of zinc-blende and wurtzite phases, according to the x-ray analysis. A Te crystalline phase is detected for Ts>550 °C.