Near-band-edge optical properties of MBE-grown ZnSe epilayers on GaAs by modulation spectroscopy

R. C. Tu, Y. K. Su, Y. S. Huang, S. J. Chang

Research output: Contribution to journalConference articlepeer-review


A study of near-band-edge optical properties on ZnSe epilayers grown on GaAs substrates using various modulation techniques is presented. We compare the contactless electroreflectance (CER) and piezoreflectance (PzR) spectra to ascertain that our ZnSe epilayers of 1.2 μm in thickness grown on GaAs substrates are under a biaxial tensile strain. The defect-related transitions near the ZnSe/GaAs interface are also compared by identifying the photoreflectance (PR) and other spectra. In addition, in order to observe the temperature-dependent energy splitting and strains, we present a detailed investigation of the heavy and light-hole related transition energies as a function of temperature in the 15-200 K range by identifying the excitonic signatures in the CER spectra. We have also calculated the energy splitting between heavy and light-hole valence bands by utilizing the temperature-dependent elastic constants for ZnSe and the thermal-expansion coefficients for ZnSe and GaAs. Both the experimental result and the theoretical calculation have shown a similar trend that the biaxial tensile strains decrease in magnitude with increasing temperatures in the 1.2 μm ZnSe epilayer grown on a GaAs substrate.

Original languageEnglish
Pages (from-to)325-337
Number of pages13
JournalProceedings of SPIE - The International Society for Optical Engineering
Publication statusPublished - 1998
EventOptoelectronic Materials and Devices - Taipei, Taiwan
Duration: 1998 Jul 91998 Jul 11

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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