Ultrafast carrier relaxation in GaN, In0.05Ga0.95N, and an In0.07Ga0.93N/In0.12Ga0.88N multiple quantum well

Article

关键词: STIMULATED-EMISSION;    BAND-GAP;    EXCITON LOCALIZATION;    OPTICAL-PROPERTIES;    GALLIUM NITRIDE;    LASER-DIODES;    INGAN;    SPECTROSCOPY;    DYNAMICS;    PHOTOLUMINESCENCE;   

DOI  :  10.1103/PhysRevB.67.155308

来源: SCIE

【 摘 要 】

Room-temperature, wavelength-nondegenerate ultrafast pump/probe measurements were performed on GaN and InGaN epilayers and an InGaN multiple quantum well (QW) structure. Carrier relaxation dynamics were investigated as a function of excitation wavelength and intensity. Spectrally resolved sub-picosecond relaxation due to carrier redistribution and QW capture was found to depend sensitively on the wavelength of pump excitation. Moreover, for pump intensities above a threshold of 100 muJ/cm(2), all samples demonstrated an additional emission feature arising from stimulated emission (SE). SE is evidenced as accelerated relaxation (<10 ps) in the pump-probe data, fundamentally altering the redistribution of carriers. Once SE and carrier redistribution is completed, a slower relaxation of up to 1 ns for GaN and InGaN epilayers, and 660 ps for the multiple QW sample, indicates carrier recombination through spontaneous emission.

【 授权许可】

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