Morphology and transport rates of mixed IV-VI compounds in micro-gravity
Abstract
The positive effects of micro-gravity on crystal growth and basic properties of the vapor transport reaction were established by analyzing the results of three transport experiments of multicomponent systems performed during the Apollo-Soyuz mission. The systems employed were GeSe0.99Te0.01-GeI4, GeS0.98Se0.02-GeCl4, and GeS-GeCl4-Ar. The crystallographic analysis is based on a direct comparison of spaceand earth-grown (prototype) crystals, employing X-ray diffraction, microprobe, microscopic, and chemical etching techniques. The results demonstrate a considerable improvement of the space-grown crystals in terms of chemical and crystalline homogeneity, surface morphology, and bulk perfection relative to earth specimens. The confirmation of greater mass transport rates than predicted for diffusion-controlled transport in micro-gravity suggests the existence of 'thermochemically' induced convective motion in chemical vapor transport systems.
- Publication:
-
Journal of the Electrochemical Society
- Pub Date:
- July 1977
- DOI:
- 10.1149/1.2133489
- Bibcode:
- 1977JElS..124.1095W
- Keywords:
-
- Crystal Growth;
- Gravitational Effects;
- Semiconductors (Materials);
- Transport Properties;
- Vapor Phases;
- Apollo Soyuz Test Project;
- Crystallography;
- Etching;
- Germanium Compounds;
- Microanalysis;
- Microgravity Applications;
- Microstructure;
- Morphology;
- Reaction Kinetics;
- Selenides;
- Space Commercialization;
- X Ray Diffraction;
- Solid-State Physics