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Proceedings Paper

Heteroepitaxiai Growth Of CdTe And CdHgTe By Close-Spaced Vapor Transport
Author(s): Michel Barbe; Gerard Cohen-Solal
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Paper Abstract

Reactive close spaced vapor transport in hydrogen has been used to deposit II-VI compound semiconductors on (0001) sapphire substrates. The CdTe grown layer are (111) oriented with some twinning as clearly shown by Laue diffraction patterns. For a substrate at 500°C the growth process is three dimensional and in a coalescence regime leading to highly facetted and oriented pyramidal surfaces with a (111) growth axis. From the DDX measured value, 2000 arc-sec, one mights infer that the crystallinity is relatively poor. However FL spectra show near-band-edge and exciton emission lines with a linewidth of less 0.6 meV at 2K. Also n-type In-doped films have typically electron concentration of 1015 -1016 cm-3 with mobilities of few hundreds cm2 V-1 5-1 at room temperature. The CdTe epilayers on GaAs (100) are either (111) or (100), or a (111) + (100) mixture.The layers have textured surfaces with pyramids. In the (111) oriented growth the basis of the pyramid is triangular with epitaxial relation CdTe (211)//GaAs (011). High resolution TEM studies reveal sharp interface. The as-grown layers are n type (1015 - 1017 cm-3) with mobility at 300 K of 390 cm2 V-1 s-1, and the P. spectra shows near-band-edge recombination with line-width of 1.5 meV at 2K. In relevance to I.R. focal plane array technology, heteroepitaxy of CdHgTe on GaAs is obtained by growing HgTe upon one layer of CdTe with a subsequent interdiffusion heat-treatment process. Hall mobilities of 5000 (room temperature) and 8000 (20K) cm2 V-1 .5-1 for (100) layers are measured.

Paper Details

Date Published: 15 August 1988
PDF: 5 pages
Proc. SPIE 0944, Growth of Compound Semiconductor Structures II, (15 August 1988); doi: 10.1117/12.947374
Show Author Affiliations
Michel Barbe, C.N.R.S. (France)
Gerard Cohen-Solal, C.N.R.S. (France)

Published in SPIE Proceedings Vol. 0944:
Growth of Compound Semiconductor Structures II
Anupam Madhukar, Editor(s)

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