Deep-level-transient spectroscopy of heavily Al-doped ZnSe layers grown by molecular-beam epitaxy

D. C. Oh, T. Takai, T. Hanada, M. W. Cho, T. Yao, J. S. Song, J. H. Chang, F. Lu

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6 Citations (Scopus)

Abstract

Using deep-level-transient spectroscopy, we have investigated deep levels in heavily Al-doped ZnSe layers grown by molecular-beam epitaxy. The Al concentration of the ZnSe layers lies in the range of 5 × 10 18-9 × 1018 cm-3. The ZnSe:Al layers exhibit two electron-trap centers with the thermal activation energies of 0.16 eV (ND1) and 0.80 eV (ND2). ND2 is a dominant trap center with a trap density of 3 × 1016 cm-3, while the trap density of ND1 is estimated to be 2 × 1015 cm-3. However, ND2 shows anomalous behaviors, different from isolated point defects, in the following points: (1) the emission peak of ND2 moves to the low temperature side with increasing filling pulse duration; (2) the emission peak of ND2 is broader than theoretically calculated one for an isolated point defect; and (3) the capacitance-transient curve is nonexponential. It is observed by high-resolution x-ray diffraction that heavy Al doping results in the relaxation and plastic deformation of the ZnSe lattice. These behaviors can be ascribed to extended defects with a broad energy spectrum. By assuming a Gaussian distribution of deep levels due to extended defect, the broad emission peak is successfully simulated.

Original languageEnglish
Article number6
Pages (from-to)7332-7337
Number of pages6
JournalJournal of Applied Physics
Volume96
Issue number12
DOIs
Publication statusPublished - 2004 Dec 15

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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    Oh, D. C., Takai, T., Hanada, T., Cho, M. W., Yao, T., Song, J. S., Chang, J. H., & Lu, F. (2004). Deep-level-transient spectroscopy of heavily Al-doped ZnSe layers grown by molecular-beam epitaxy. Journal of Applied Physics, 96(12), 7332-7337. [6]. https://doi.org/10.1063/1.1814170