Deep-level emissions in GaAsN/GaAs structures grown by metal organic chemical vapor deposition

Jenn-Fang Chen*, C. T. Ke, P. C. Hsieh, C. H. Chiang, Wei-I Lee, S. C. Lee

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

This work presents the deep-level photoluminescence of coherently strained GaAsNGaAs quantum-well (QW) structures with various GaAsN thicknesses and N contents. A broad deep-level emission at ∼1.1 eV is observed, whose wavelength is redshifted as the GaAsN thickness increases. Based on its energy separation from the QW emission, this emission is attributed to a transition between the QW electron ground state and a deep level at ∼0.2 eV above the GaAsN valence-band (VB) edge. This level is shown to be tied to the GaAs band edge. A transition between this level and the GaAs conduction band allows the GaAsN-GaAs band alignment to be evaluated. A type II band lineup is obtained with VB offsets of 0.03 and 0.002 eV for N=0.6% and 1.8%, respectively. The decreased VB offset suggests a transition from type II to type I with increasing N content. Thermal annealing effectively removes this level and improves the QW emission. The concentration of this level is not clearly correlated with N content, suggesting that this level is induced by a low-temperature growth of the GaAsN layer to suppress the composition fluctuation. Given its energy, this level is tentatively assigned to VGa.

Original languageEnglish
Article number123515
JournalJournal of Applied Physics
Volume101
Issue number12
DOIs
StatePublished - 2 Aug 2007

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