Superlattice period dependence on nonradiative recombination centers in the n -AlGaN layer of UV-B region revealed by below-gap excitation light

M. Ismail Hossain*, Yuri Itokazu, Shunsuke Kuwaba, Norihiko Kamata, Noritoshi Maeda, Hideki Hirayama

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Nonradiative recombination (NRR) centers in n-AlGaN layers of UV-B AlGaN samples with different numbers of superlattice (SL) periods (SLPs), grown on the c-plane sapphire substrate at 1150 °C by the metalorganic chemical vapor deposition technique, have been studied by using below-gap-excitation (BGE) light in photoluminescence (PL) spectroscopy at 30 K. The SLP affects the lattice relaxation of the SL and n-AlGaN layer. The PL intensity decreased by the superposition of BGE light of energies from 0.93 eV to 1.46 eV over the above-gap-excitation light of energy 4.66 eV, which has been explained by a two-level model based on the Shockley-Read-Hall statistics. The degree of PL quenching from n-AlGaN layers of the sample with SLP 100 is lower than those of other samples with SLP 50, 150, and 200. By a qualitative simulation with the dominant BGE energy of 1.27 eV, the density ratio of NRR centers in n-AlGaN layers of 50:100:150:200 SLP samples is obtained as 1.7:1.0:6.5:3.4. This result implies that the number of SLP changes lattice relaxation and determines the density of NRR centers in the n-AlGaN layer, which affects the performance of LEDs.

Original languageEnglish
Article number035224
JournalAIP Advances
Volume10
Issue number3
DOIs
StatePublished - 1 Mar 2020
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2020 Author(s).

ASJC Scopus subject areas

  • General Physics and Astronomy

Fingerprint

Dive into the research topics of 'Superlattice period dependence on nonradiative recombination centers in the n -AlGaN layer of UV-B region revealed by below-gap excitation light'. Together they form a unique fingerprint.

Cite this