Optimization of sensor materials using physical vapor transport growth method

During the past several decades physical vapor transport (PVT) method has been extensively used for developing laser and electronic and optical sensor materials especially for incongruent and high vapor materials. Extensive careful studies of the NASA Marshall Space Flight Center on ZnSe growth by PVT has demonstrated that both thermal and solutal convection play very important roles on the quality of crystals and can be controlled by microgravity experiments. In case, the growth is performed by sputtering or systems such as DENTON, it is very difficult to control fluid flow and both thermal and solutal convective flows. We have demonstrated that by controlling the transport path, temperature of substrate and source and using purified source micron size thick ness can be achieved. We will present the experimental results of pure and doped lead selenide (PbSe) which demonstrated various morphologies and bandgap based on size of particles based on growth condition.