Lattice parameter anomaly in an MOCVD CdTe epitaxial layer grown on a GaAs substrate

Conference · Thu May 01 04:00:00 EDT 1986

OSTI ID:5601523

Staudemann, J L; Horning, R D; Knox, R D; Arch, D K; Schmit, J L; Bonse, U; Testardi, L R; Weber, W

The anomalous behaviors of the CdTe and GaAs lattice parameters below 120/sup 0/K for a composite system is reported. They concern a 3 ..mu..m thick (1,0,0) single crystal CdTe epitaxial layer on a (1,0,0) single crystal GaAs substrate. The epilayer was deposited at 410/sup 0/C by MOCVD. This x-ray lattice parameter study was done in the temperature range between about 8/sup 0/K and 300/sup 0/K. The lattice parameters of the composite system are compared to those of the corresponding bulks. The bulk lattice parameter variations as a function of the temperature were also measured and compare well with the appropriate changes of the thermal expansion coefficients taken from the literature. Our results show that the lattice parameters perpendicular to the surface of both the GaAs substrate and the CdTe epilayer shrink four times more than the corresponding bulks when the samples are cooled down to 10/sup 0/K. It is further seen that there is no compensation effect between the elements of the composite system; that is, the lattice parameters of the two materials change in the same direction as if the composite system - the epilayer and the thickness of the substrate which is probed by the x-rays - would behave as a new material with entirely new physical properties.

• Research Organization: Ames Lab., IA (USA)
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 5601523
• Report Number(s): IS-M-577; CONF-8605111-3; ON: DE86011438
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
ARSENIC COMPOUNDS
ARSENIDES
CADMIUM COMPOUNDS
CADMIUM TELLURIDES
CHALCOGENIDES
EPITAXY
EXPANSION
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
LATTICE PARAMETERS
LAYERS
LOW TEMPERATURE
PNICTIDES
TELLURIDES
TELLURIUM COMPOUNDS
TEMPERATURE DEPENDENCE
THERMAL EXPANSION