Influence of Internal Electric Field on the Recombination Dynamics of Localized Excitons in an InGaN Double-Quantum-Well Laser Diode Wafer Operated at 450 nm

Takeyoshi Onuma, Shigefusa F. Chichibu, Toyomi Aoyama, Kiyomi Nakajima, Parhat Ahmet, Takashi Azuhata, Toyohiro Chikyow, Takayuki Sota, Shin Ichi Nagahama, Takashi Mukai

研究成果: Article査読

17 被引用数 (Scopus)

抄録

Optical and structural properties of an InGaN double-quantum-well (DQW) laser diode (LD) wafer that lased at 450 nm were investigated to discuss an enormous impact of a polarization-induced electric field on the recombination dynamics in InGaN quantum structures. The quantum-well (QW) structure was shown to have the well thickness as thin as approximately 1 nm and InN molar fraction x of approximately 14%. The gross effective electric field in the QW (F QW) was estimated to be 490kV/cm from the Franz-Keldysh oscillation (FKO) period in the electroreflectance (ER) spectrum, implying that an internal piezoelectric field (Fpiz) of approximately 1.4MV/cm was cancelled by the pn junction built-in field (Fbi) and Coulomb screening due to carriers in the DQW. The magnitude of FQW can be further weakened by applying reverse bias (VR) on the junction; the decrease in the photoluminescence (PL) lifetime at low temperature measured under VR was explained to be due to a recovery of electron-hole wavefunction overlap for small VR (|VR|<4 V), and due mainly to the tunneling escape of carriers through the barriers for larger VR. By applying an appropriate VR smaller than 4V, electron-hole wavefunction overlap, which had been separated vertically along the c-axis due to quantum-confined Stark effect, could be partially recovered, and then the time-resolved PL signals exhibited a less-pronounced stretched exponential decay, giving a scaling parameter (0β) of 0.85 and effective in-plane localization depth (E0) of 40-50 meV for the spontaneous emission. These values were closer to those of much homogeneous QWs compared to those reported previously for InGaN QWs having similar InN molar fractions. The use of very thin QWs is considered to bring easier Coulomb screening of F QW and population inversion under high excitation conditions.

本文言語English
ページ(範囲)7276-7283
ページ数8
ジャーナルJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
42
12
DOI
出版ステータスPublished - 2003 12

ASJC Scopus subject areas

  • 工学(全般)
  • 物理学および天文学(全般)

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