Open AccessElectron–hole plasma induced band gap renormalization in ZnO microlaser cavities
Author(s) -
Jun Dai,
Chunxiang Xu,
Toshihiro Nakamura,
Yueyue Wang,
Jitao Li,
Yi Lin
Publication year - 2014
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.22.028831
Subject(s) - lasing threshold , materials science , femtosecond , whispering gallery wave , full width at half maximum , band gap , excitation , optoelectronics , laser , blueshift , photoexcitation , optics , atomic physics , physics , wavelength , excited state , resonator , photoluminescence , quantum mechanics
We report electron-hole plasma (EHP) lasing in hexagonal ZnO microrods and thin nanobelts. Under the excitation of 325 nm line femtosecond pulsed laser, ultraviolet whispering-gallery mode (WGM) lasing was observed from hexagonal ZnO microrods. When EHP was formed at high excitation energy density, the center wavelength of the WGM lasing band presented a redshift from 387.5 nm to 397.5 nm, and the full width of half maximum (FWHM) of the WGM lasing band increased from 2.5 nm to 7 nm. Each lasing mode showed obvious blueshift and broadening. Such lasing characteristics were attributed to the band gap renormalization (BGR) due to the high carrier concentration at the EHP condition. In addition, EHP Fabry-Perot (F-P) mode lasing from thin ZnO nanobelt was also observed and discussed. According to the phenomenological BGR calculation with including the carrier density dependent screening effect, the values of the band gap of ZnO at different excitation energy densities were obtained, which agree well with the experimental results.