VERTICAL GRADIENT FREEZE GROWTH OF TWO INCHES Cd1-xZnxTe1-ySey INGOTS WITH DIFFERENT Se CONTENT

Abstract

Abstract Two inches in diameter and four inches in length quaternary alloy Cd1-xZnxTe1-ySey (CZTS) ingots have been grown by the Vertical Gradient Freeze Method (VGF) for two different Se concentrations (y = 0.02 and 0.07). The compositional and crystallographic properties, as well as defect morphology of the ingots have been analysed using EDX, TXRF, XRD and IR microscopy. Despite of using these two extreme Se values proposed in the literature, CZTS continues to maintain the proper zinc blende structure of CZT. However, the addition of selenium has the effect of shifting the diffraction peaks to higher angles, or what is the same, to reduce the Cd1-xZnxTe (CZT) constant lattice. It is observed that the addition of Se also favours the reduction of bubble formation along the ingots due to cadmium deficiency and change in Zn concentration along the growth CZTS ingot direction respect to CZT ingot. The VGF growth method provides great confidence and reproducibility since both ingots share similar features in terms of dimensions and defects formation.