Fine tuning of the emission of ultra-thin quantum wells of CdSe and CdTe by modification of the growth temperature

I. Hernández-Calderón, J. C. Salcedo-Reyes, A. Alfaro-Martínez, M. García-Rocha

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Ultra-thin quantum wells (UTQWs) of CdTe and CdSe should present a emission energy as a function of thickness, however, we have observed that depending on substrate temperature the peak energy is modified: the higher the growth temperature the larger the blue shift. Considering (i) a chemical interaction that produces the substitution of Cd atoms by Zn atoms at the QW-barrier interface, and, (ii) the large Bohr radius of the excitons in II-VI semiconductors, we argue that a few percent substitution of Cd atoms by Zn atoms is perceived as a change in average composition and not as a thickness fluctuation. Since the Cd substitution is a thermally activated process, a larger blue shift is expected at the higher temperatures. Therefore, the UTQWs can be described as made of Zn1-xCdxSe or Zn 1-xCdxTe alloys with high Cd content, x∼1 at the lower substrate temperatures (Ts). Then, the proper selection of T s can be advantageously employed for fine tuning of the excitonic emission in the energy region between that of UTQWs of the pure binary compound with thickness difference of 1 ML, making possible to cover continuously the visible spectral region with CdTe and CdSe UTQWs.

Original languageEnglish
Pages (from-to)985-988
Number of pages4
JournalMicroelectronics Journal
Volume36
Issue number11
DOIs
StatePublished - Nov 2005
Externally publishedYes

Keywords

  • Atomic layer epitaxy
  • CdSe
  • CdTe
  • Excitons
  • II-VI semiconductors
  • Photoluminescence
  • Quantum wells
  • Ultra-thin quantum wells

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