Unusual near-band-edge photoluminescence at room temperature in heavily-doped ZnO:Al thin films prepared by pulsed laser deposition

Bhaskar Chandra Mohanty, Deuk Ho Yeon, Sachindra Nath Das, Ji Hye Kwak, Kyung Hoon Yoon, Yong Soo Cho

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Room temperature photoluminescence (PL) properties of heavily-doped ZnO:Al thin films (with carrier concentration n in the range of 5-20 × 10 20 cm-3) prepared by pulsed laser deposition have been investigated. Despite their high carrier concentration, the films exhibited strong room temperature near-band-edge bound excitons at ∼3.34 eV and an unusual peak at ∼3.16 eV, and negligible deep-level emission even for the films deposited at a temperature as low as 25 C. The radiative efficiency of the films increased with growth temperature as a result of increased n and improved crystallinity. A large blue shift of optical band gap was observed, which is consistent with the n-dependent Burstein-Moss and band gap-renormalization effects. Comparison of the results of the PL and optical measurements revealed a large Stokes shift that increased with increase in n. It has been explained by a model based on local potential fluctuations caused by randomly-distributed doping impurities.

Original languageEnglish
Pages (from-to)610-615
Number of pages6
JournalMaterials Chemistry and Physics
Volume140
Issue number2-3
DOIs
Publication statusPublished - 2013 Jul 15

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics

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