||Comparative Study on Nonradiative Recombination Centers in Proton Irradiated InAs/GaAs Quantum Dot Structure by Two Wavelength Excited Photoluminescence
D. Haque, M. ,
Kamata, N. ,
Sato, ShinichiroM. Hubbard, S.
Proceedings of the 44th IEEE Photovoltaic Specialists Conference
2018-02 , IEEE
Comparative study on nonradiative recombination (NRR) centers in InAs/GaAs quantum dot (QD) structure generated by 3 MeV proton irradiation is performed by two wavelength excited photoluminescence (TWEPL). The above-gap excitation (AGE) source of 2.33 eV or 1.26 eV is used to excite GaAs host material or InAs QDs, respectively. The QD PL intensity decreased after irradiation of below-gap excitation (BGE) of 0.75 eV over AGE, indicating a pair of NRR centers activated. The proton irradiation at fluence of 7×1011cm-2 reduces the NRR density, while that of 4×1012cm-2 increases it. Defect formation, carrier injection and their fluence dependence explain experimental results.