Abstract

Physical vapor transport experiments of GeSe in the presence of 2 atm xenon and for a nominal temperature difference of 600°C500°C were performed under 1g, 5g, and 10g acceleration conditions. Under high acceleration and destabilizing conditions, the GeSe crystals are generally larger than those under 1g, stabilizing, and up to three orders of magnitude larger in surface area than those under 1g, destabilizing conditions. The mass transport rates of the 5g and 10g destabilizing experiments are considerably greater than those of the 10g, stabilizing and 1g experiments. The observed increase in mass flux (under destabilizing conditions) with acceleration is significantly greater than the anticipated dependence (mass flux proportional to g^1/4 for laminar, boundary-layer driven free convection. In view of the considerable convection under high acceleration, destabilizing conditions, the surface morphology and bulk crystallinity of the large crystal platelets are unexpectedly good.