Hot wall epitaxy

• Published in: Thin Solid Films Vol. 49; no. 1; pp. 3 - 57
• Main Author: Lopez-Otero, A.
• Format: Book Review Journal Article
• Language: English
• Published: Elsevier B.V 15.02.1978
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/0040-6090(78)90309-7

Thin films now occupy a prominent place in basic research and solid state technology. Until recently, however, the quality of epitaxial thin film materials has been consistently inferior to that of the bulk. In the last few years considerable effort has been expended and different methods have been used in order to try to remedy this situation. One approach is that of hot wall epitaxy where the emphasis is put on the growth of epitaxial layers under conditions as near as possible to thermodynamic equilibrium. With this method the achievement of high quality luminescent and electro- optic films of II–VI materials has been made possible without the need for post- growth heat treatments. The effective use of compensating sources together with the main source material allows the preparation of IV–VI films with carrier concentrations one to two orders of magnitude lower than those of the bulk (down to 8×10 15 cm −3 for PbTe). Mobilities as high as that of the best grown bulk material (4.1×10 6 cm 2 V −1 s −1 for PbTe) have also been obtained. The availability of material of this quality permits basic experiments which would be difficult or even impossible to perform with bulk materials or films of lesser quality. Hot wall epitaxy has also made it possible to fabricate infrared heterojunction lasers which operate in the continuous wave mode up to a temperature of 96 K in the wavelength region around 5 μm. Pulsed operation has been achieved up to 190 K.