Title :
Spectrally Resolved Interband and Intraband Transitions by Two-Step Photon Absorption in InGaAs/GaAs Quantum Dot Solar Cells
Author :
Tamaki, Ryo ; Shoji, Yozo ; Okada, Yoshitaka ; Miyano, Kenjiro
Author_Institution :
Res. Center for Adv. Sci. & Technol., Univ. of Tokyo, Tokyo, Japan
Abstract :
Two-step photon absorption processes in a self-organized In0.4Ga0.6As/GaAs quantum dot solar cell have been investigated by means of infrared (IR) light-biased change in external quantum efficiency (ΔEQE) spectroscopy at 9 K. In this paper, not only interband transitions but intraband transitions were both spectrally resolved by utilizing wavelength tunable intense mid-IR pulsed laser as the IR bias light source. The obtained EQE enhancement was attributed from reexcitation of photocarriers captured by quantum dots. The bound-to-continuum intraband transition probability was estimated to be about 8% by irradiating 100-suns-equivalent IR bias light.
Keywords :
III-V semiconductors; gallium arsenide; indium compounds; self-assembly; semiconductor quantum dots; solar cells; IR bias light source; In0.4Ga0.6As-GaAs; InGaAs-GaAs quantum dot solar cells; bound-to-continuum intraband transition probability; external quantum efficiency spectroscopy; photocarrier reexcitation; self-organized quantum dot solar cell; spectrally resolved interband transition; spectrally resolved intraband transition; temperature 9 K; two-step photon absorption processes; wavelength tunable intense mid-IR pulsed laser; Absorption; Gallium arsenide; Indium gallium arsenide; Photonics; Photovoltaic cells; Quantum dots; Stationary state; Gallium arsenide; III–V semiconductor materials; III???V semiconductor materials; indium gallium arsenide; photovoltaic cells; quantum dots; spectroscopy;
Journal_Title :
Photovoltaics, IEEE Journal of
DOI :
10.1109/JPHOTOV.2014.2368712
