Successful growth of Cu2Se-free CuGaSe2 by migration-enhanced epitaxy

Miki Fujita, Tomohiro Sato, Tsuyoshi Kitada, Atsushi Kawaharazuka, Yoshiji Horikoshi

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

CuGaSe2 films were grown on GaAs (001) substrates by migration enhanced epitaxy, where Cu Ga and Se are alternately deposited. The in situ reflection high energy electron diffraction observation during growth revealed that the segregation of Cu2Se on CuGaSe2 can be detected by anomalous diffraction patterns. When the Cu2Se segregation takes place, a distorted pattern appears in both Cu Ga and Se deposition periods. By optimizing the flux ratios, the anomalous diffraction disappears, and we succeeded in growing high quality CuGaSe2 single crystal layers free from Cu2Se segregation on GaAs (001) substrates. The authors also found that, in the CuGaSe2/GaAs wafers with Cu2Se segregation, a high density of voids is often observed at the substrate surface. These voids disappeared when the Cu2Se-free growth conditions were employed. Ga atoms near the GaAs substrate surface were probably drawn out by excess Cu atoms in the growing layer to form CuGaSe2, leading to the creation of voids with fairly large size.

Original languageEnglish
Article number02B126
JournalJournal of Vacuum Science and Technology B:Nanotechnology and Microelectronics
Volume30
Issue number2
DOIs
Publication statusPublished - 2012

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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