Pulsed Plasma Preparation for LWIR Materials
Abstract
The objective of this programme was to apply the capabilities of the novel STL pulsed plasma process to the preparation and screening of new infra- red materials. The area of specific interest is transmission window materials for the far infra-red (8-12 micron), which perform better than ZnS in at least one respect, without any trade-off in other properties. Eight binary phosphides, novel in both composition and structure, have been investigated for use in IR applications. Excluding cadmium phosphide, in which the band gap was too small, all the phosphides are harder than ZnS. In addition, most are IR transparent in the regions of interest, though hydrogen inclusion tends to occur in those phosphides with the lighter cations (causing absorption near 12 micron) and silicon and aluminum phosphides exhibit absorption. Aluminum phosphides have for the first time been made stable, at least at the higher phosphorus contents, and addition of zinc to silicon phosphide has demonstrated the potential of ternary additions in beneficially modifying absorption characteristics and mechanical properties. In view of the latter data, the ternary zinc germanium phosphide offers great potential. This ternary is expected to be harder than either binary, with a larger band gap, and any weak absorptions beyond 12 micron are expected to move further away. Keywords: Pulsed plasma, Thin film deposition, Complete gas dissociation, Long wavelength, Infra-red, Amorphous super phosphides.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 18, 1990
- Accession Number
- ADA224241
Entities
People
- G. A. Scarsbrook