Heteroepitaxial CdTe(111) grown by MBE on nominally flat and misoriented Si(001) substrates: Characterization by electron microscopy and optical methods

S. C Y Tsen, David Smith, J. W. Hutchins, Brian Skromme, Y. P. Chen, S. Sivananthan

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Abstract

Transmission electron microscopy (TEM), and low temperature reflectance and photoluminescence (PL) have been used to characterize heteroepitaxial CdTe(111) layers grown by molecular beam epitaxy directly onto nominally flat and misoriented Si(001) substrates. TEM observations confirmed that 1° offcut toward [110] in the Si(001) substrate suppressed formation of double domains, while increasing the azimuthal angle of the offcut relative to [110] suppressed twin formation. Under optimized growth conditions, residual twinning defects disappeared within about 2 μm from the substrate. Atomic-scale details of interfaces in this system were successfully recorded. Clear splitting of exciton states at the direct gap in optical reflectance and PL spectra demonstrated the existence of residual biaxial tensile strain of about 7 × 10-4 in the CdTe layers, due to thermal expansion mismatch. A strain-shifted neutral acceptor-bound exciton peak dominated the 1.7 K photoluminescence spectrum, together with donor-to-acceptor and band-to-acceptor transitions involving a 49 meV shallow acceptor level. The sharpness of bound exciton peaks (about 0.6 meV full width at half maximum) supported the high layer quality.

Original languageEnglish (US)
Pages (from-to)58-63
Number of pages6
JournalJournal of Crystal Growth
Volume159
Issue number1-4
StatePublished - Feb 1996

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Molecular beam epitaxy
Excitons
Electron microscopy
electron microscopy
Photoluminescence
excitons
optics
photoluminescence
Substrates
Transmission electron microscopy
reflectance
transmission electron microscopy
Tensile strain
Twinning
sharpness
twinning
Full width at half maximum
Thermal expansion
thermal expansion
molecular beam epitaxy

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Heteroepitaxial CdTe(111) grown by MBE on nominally flat and misoriented Si(001) substrates : Characterization by electron microscopy and optical methods. / Tsen, S. C Y; Smith, David; Hutchins, J. W.; Skromme, Brian; Chen, Y. P.; Sivananthan, S.

In: Journal of Crystal Growth, Vol. 159, No. 1-4, 02.1996, p. 58-63.

Research output: Contribution to journalArticle

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AU - Hutchins, J. W.

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