X-ray-diffraction characterization of CdTe epitaxial layers on GaAs substrates as a function of temperature

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:7078016

Horning, R D

X-ray-diffraction methods were used to study the structural and thermal properties of CdTe epitaxial layers on GaAs substrates. The technique of precession photography is introduced as an extremely useful method for qualitative characterization of thin films, and reveals twin faults in (1,1,1) oriented CdTe epilayers. Measurements of the Bragg reflections as a function of temperature were made between 10 and 360 K. These measurement reveal anomalous behavior in the lattice parameters of both the substrate and the epilayer in a (0,0,1) oriented sample deposited at 410/sup 0/C. The overall change in the CdTe lattice parameter in this temperature range was about five times larger than in bulk CdTe, and the change in the substrate lattice parameter was about three times the bulk value. These anomalies were absent in a similar sample deposited at 380/sup 0/C. Similar measurements were made on GaAs and CdTe single crystals for comparison. The Debye temperatures extracted from the integrated intensities of the reflections perpendicular to the surface are approx. 250 K for the GaAs substrates and approx. 142 K for the CdTe epilayers. These are the same as the corresponding values in single crystals of GaAs and CdTe, revealing no significant change in the overall vibrational properties. The Debye temperatures extracted form reflections not perpendicular to the surface are significantly lower.

• Research Organization: Iowa State Univ. of Science and Technology, Ames (USA)
• OSTI ID: 7078016
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
42 ENGINEERING
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ARSENIC COMPOUNDS
ARSENIDES
BRAGG REFLECTION
CADMIUM COMPOUNDS
CADMIUM TELLURIDES
CHALCOGENIDES
COHERENT SCATTERING
DEBYE TEMPERATURE
DIFFRACTION
EPITAXY
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
HIGH TEMPERATURE
LATTICE PARAMETERS
LAYERS
PNICTIDES
REFLECTION
SCATTERING
SUBSTRATES
TELLURIDES
TELLURIUM COMPOUNDS
TEMPERATURE DEPENDENCE
X-RAY DIFFRACTION