Crystal quality improvement of ZnTe (1 1 0) thin film prepared on sapphire by increasing nuclei density on substrate surface

Shotaro Kobayashi*, Kota Sugimoto, Kaito Tsuboi, Masakazu Kobayashi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

ZnTe thin films were prepared on r, S-plane nanofacet substrates to achieve a high-crystal-quality layer with a (1 1 0) orientation. Scanning electron microscopy was used to study the nucleation process. Selective formation of growth nuclei can be achieved by controlling the substrate temperature. The low-temperature grown amorphous layers changed to nuclei by annealing. The surface amorphous layer was completely removed when the annealing temperature was too high. Zn beam irradiation during the annealing removed materials selectively from the r-nanofacet. Migration-enhanced epitaxy (MEE) was introduced to enlarge the nuclei size, and a thick-layer growth by conventional molecular beam epitaxy (MBE) followed. The MEE sequence was increased up to 1200 cycles, and the substrate temperature for MEE and MBE was set to higher temperatures than the conventional MBE substrate temperature (the conventional substrate temperature was around 340 °C). The crystal quality of the thin film was analyzed using the X-ray pole figure, θ–2θ measurements and photoluminescence. (1 1 0) oriented layer formation perpendicular to the substrate surface was confirmed after introducing those techniques. The low-temperature photoluminescence measurement indicated the high quality of the thick layer.

Original languageEnglish
Article number126825
JournalJournal of Crystal Growth
Volume596
DOIs
Publication statusPublished - 2022 Oct 15

Keywords

  • A1. Nucleation
  • A3. Migration Enhanced Epitaxy
  • A3. Molecular Beam Epitaxy
  • Nanofacet
  • Photoluminescence
  • Zn irradiation

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry

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