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

Technical Report · Sat Nov 01 04:00:00 EST 1986

OSTI ID:7151923

Horning, R D

X-ray diffraction methods have been used to study the structural and thermal properties of CdTe epitaxial layers on GaAs substrates. Precession photography revealed twin faults in (1,1,1) oriented CdTe epilayers. Measurements of the Bragg reflections between 10 and 360/sup 0/K 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. The Debye temperatures derived from perpendicular reflections are 250/sup 0/K for the GaAs substrates and 142/sup 0/K for the CdTe epilayers. These are the same as for single cyrstals of GaAs and CdTe. The Debye temperatures from reflections not perpendicular to the surface are significantly lower. The Debye theory and the One-Particle Potential model are used in the above analyses. The Debye-Einstein theory does not explain the observed behavior any better than the Debye theory. 140 refs., 53 figs.

• Research Organization: Ames Lab., IA (USA)
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 7151923
• Report Number(s): IS-T-1250; ON: DE87003047
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
ARSENIC COMPOUNDS
ARSENIDES
BRAGG REFLECTION
CADMIUM COMPOUNDS
CADMIUM TELLURIDES
CHALCOGENIDES
COHERENT SCATTERING
CRYSTALS
DEBYE TEMPERATURE
DIFFRACTION
ENERGY LEVELS
EPITAXY
EXCITED STATES
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
LATTICE PARAMETERS
LAYERS
LOW TEMPERATURE
MEDIUM TEMPERATURE
MONOCRYSTALS
PHONONS
PNICTIDES
QUASI PARTICLES
REFLECTION
SCATTERING
STRUCTURE FACTORS
TELLURIDES
TELLURIUM COMPOUNDS
TEMPERATURE DEPENDENCE
ULTRALOW TEMPERATURE
VERY LOW TEMPERATURE
VIBRATIONAL STATES
X-RAY DIFFRACTION