Growth of HgCdTe by Modified Molecular Beam Epitaxy (MBE)
Semi-annual technical rept. no. 2, 1 Sep 1979-29 Feb 1980
ROCKWELL INTERNATIONAL CORP THOUSAND OAKS CA SCIENCE CENTER
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An investigation was made on the deposition of HgCdTe thin film on CdTe by irradiating the bulk source material with high power laser pulses. The morphological features and stoichiometric composition depend very strongly on the laser characteristics and the scanning rate. Under very high power operation, the dominant deposition process is the condensation of micron size molten globules blown-off from the source material. At lower power level, the film formation is largely due to the deposition of small molecular clusters. Compositional analysis of the film showed that the CdTe end of the alloy evaporated congruently, whereas the HgTe and end suffered some loss of Hg. The amount of Hg loss could be reduced by varying the laser power and the scanning rate. n-type films up to 2 micron thick were deposited in this manner and photoconductive devices were fabricated and measured. We have also made a detailed mass spectrometric study of the evaporant composition under different conditions. A model on the evaporation mechanism formulated from such information will be discussed.
- Physical Chemistry
- Electrical and Electronic Equipment