Title :
Strikingly Different Behaviors of Photoluminescence and Terahertz Generation in InGaN/GaN Quantum Wells
Author :
Guan Sun ; Ruolin Chen ; Ding, Yujie J. ; Hongping Zhao ; Guangyu Liu ; Jing Zhang ; Tansu, N.
Author_Institution :
Dept. of Electr. & Comput. Eng. & Center for Opt. Technol., Lehigh Univ., Bethlehem, PA, USA
Abstract :
We have investigated photoluminescence (PL) and terahertz (THz) generation simultaneously from multiple InGaN/GaN quantum wells (QWs) with different well periods. The PL intensity fully saturates when the period of QWs is increased up to 4. However, THz output power continuously scales up even if the period of QWs is increased up to 16. Such a behavior indicates that high-power THz wave can be generated without efficient recombination of the photogenerated carriers, since THz is only generated during the absorption process. Following the measurements of intensity and peak energy of PL together with output power and spectra of THz, we have concluded that the screening effect induced by photo-generated carriers can be neglected when the pump fluence is as low as 85 μJ/cm2.
Keywords :
III-V semiconductors; absorption coefficients; gallium compounds; indium compounds; photoluminescence; semiconductor quantum wells; terahertz wave spectra; visible spectra; wide band gap semiconductors; InGaN-GaN; absorption; photogenerated carrier recombination; photoluminescence; quantum wells; spectra; terahertz generation; Absorption; Gallium nitride; Laser beams; Laser excitation; Measurement by laser beam; Power generation; Pump lasers; Broadband terahertz (THz) wave; InGaN/GaN quantum wells (QWs); built-in field; dipole radiation; photoluminescence (PL);
Journal_Title :
Selected Topics in Quantum Electronics, IEEE Journal of
DOI :
10.1109/JSTQE.2012.2218093
