Characteristics of MOCVD-Grown High-Quality CdTe Layers on GaAs Substrates
P. W. Sze,1K. F. Yarn,1,2Y. H. Wang,3M. P. Houng,3and G. L. Chen3
Received10 Jan 1995
Accepted03 Apr 1995
Abstract
CdTe epitaxial layers are grown successfully on a (100)-GaAs substrate by metalorganic chemical vapor
deposition (MOCVD) using dimethylcadrnium (DMCd) and diethyltelluride (DETe) as alkyl sources.
The CdTe epilayers grown between 365°C and 380°C possess the best surface morphology. DETe is used
as the controlling species of this growth system. Typical growth rates are varied from 2.51µm/hr to
5.31µm/hr. Low-temperature (12K) photoluminscence (PL) measurements reveal that 380°C is the best
growth temperature and the full width at half maximum (FWHM) of the dominated peak is about
1.583eV by the bound-exciton emission of 9.38meV. The double crystal X-ray rocking curves (DCRC)
indicate that the FWHM decreases while increasing the epilayer thickness and approaches a stable value
about 80 arc sec under the growth rate of 5.2µm/hr, the growth temperature of 380°C and the
DETe/DMCd concentration ratio of 1.7. The value of 80 arc sec in FWHM is the smallest one ever
reported to date.