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.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
