Mechanisms for photon-emission enhancement with silicon doping in InGaN/GaN quantum-well structures

Yung Chen Cheng, Cheng Hua Tseng, Chen Hsu, Kung Jen Ma, Shih Wei Feng, En Chiang Lin, C. C. Yang, Jen Inn Chyi

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Material and optical analyses of three InGaN/GaN quantum-well (QW) samples with different silicon-doping conditions were conducted. Quantum-dot (QD) structures were observed in samples of silicon doping either in barriers or wells. The calibrated-radiative lifetimes in both silicon-doped samples showed the consistent trend of the formation of zero-dimensional (0-D) structure upon silicon doping. In optical characterization, the barrier-doped sample showed a blueshift of the photoluminescence (PL) peak, enhancement of integrated PL intensity, reduction of Stokes shift (SS), decrease of carrier-activation energy, and shortening of PL decay time. Except the insignificant PL peak shift, the well-doped sample showed similar trends, although they are not as prominent as the barrier-doped sample. Such results mainly originated from the reduction of the quantum-confined Stark effect (QCSE) within the clusters. Contrary to the interpretation in the past, the major mechanism for QCSE reduction is due to strain relaxation, instead of carrier screening, in conjunction with the formation of QD structures. Such a conclusion is supported by the result of smaller changes of optical behavior in the well-doped sample, in which carrier screening is expected to be more significant. In this sample, besides strain relaxation, enhanced carrier localization (CL) might represent another important mechanism for photon-emission improvement.

Original languageEnglish
Pages (from-to)375-381
Number of pages7
JournalJournal of Electronic Materials
Volume32
Issue number5
DOIs
StatePublished - May 2003

Keywords

  • InGaN/GaN
  • Photon emission
  • Quantum-well structures
  • Silicon doping

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