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Hoheisel, R.*; Gonz
lez, M.*; Lumb, M.*; Scheiman, D.*; Messenger, S. R.*; Bailey, C. G.*; Lorentzen, J.*; Tibbits, T. N. D.*; Imaizumi, Mitsuru*; Oshima, Takeshi; et al.
IEEE Journal of Photovoltaics, 4(1), p.253 - 259, 2014/01
Times Cited Count：19 Percentile：61.82(Energy & Fuels)Analysis on the radiation response of solar cells with multi quantum wells (MQW) included in the quasi-intrinsic region between the emitter and the base layer is presented. We found that in the case of MQW devices, carrier removal (CR) effects are also observed. Experimental measurements and numerical simulations reveal that with increasing radiation dose, CR can cause the initially quasi-intrinsic background doping of the MQW region to become specifically n- or p-type. This can result in a significant narrowing and even the collapse of the electric field between the emitter and the base where the MQWs are located. The implications of the CR-induced modification of the electric field on the current-voltage characteristics and on the collection efficiency of carriers generated within the emitter, the MQW region, and the base are discussed for different radiation dose conditions. This paper concludes with a discussion of improved radiation hard MQW device designs.
Gonzlez, M.*; Hoheisel, R.*; Lumb, M.*; Scheiman, D.*; Bailey, C. G.*; Lorentzen, J.*; Maximenko, S.*; Messenger, S. R.*; Jenkins, P. P.*; Tibbits, T. N. D.*; et al.
Proceedings of 39th IEEE Photovoltaic Specialists Conference (PVSC-39) (CD-ROM), p.3233 - 3236, 2013/06
The radiation response of multi quantum wall (MQW) triple junction and component cells was analyzed. Initial results show that for 1MeV electron irradiation the middle MQW cell governs the degradation of the triple junction. This is attributed the specific middle cell design, in particular the thick 0.98 
m depletion region, and alternative, more radiation hard, designs are presented. Additionally, characterization studies, including dark IV, external quantum efficiency, electroluminescence, as well as defect characterization were investigated.
Bell, G.*; Quinn, P.*; Noakes, T.*; Bailey, P.*; Takahashi, Masamitsu
no journal, ,
Medium energy ion scattering (MEIS) has been used for some years as a powerful probe of semiconductor layer structures. In particular, MEIS energy spectra can be converted to depth profiles of different atomic species in a structure with vertical resolution approaching single atomic layer thickness. However, the application of MEIS to discrete nanostructures (zero- or one-dimensional objects, rather than two-dimensional layer structures) has been very limited. We have recently analyzied InAs-GaAs quantum dot (QD) structures grown by MBE using MEIS and derived the vertical In composition profile in them. In the present work, we extended these experiments to InAs-GaAs QDs grown under different conditions at the in situ MBE facility at SPring-8, Japan. We discuss the variation of In composition profiles obtained by different MBE growth conditions.
Hoheisel, R.*; Gonzlez, M.*; Lumb, M.*; Scheiman, D.*; Messenger, S. R.*; Bailey, C. G.*; Lorentzen, J.*; Tibbits, T. N. D.*; Imaizumi, Mitsuru*; Oshima, Takeshi; et al.
no journal, ,
In this paper a detailed analysis on the radiation response of solar cells with multi quantum-wells (MQW) included in the quasi-intrinsic region between the emitter and the base layer is presented. Whilst the primary source of radiation damage of photovoltaic devices is generally associated with minority carrier lifetime reduction, we found that in the case of MQW devices another effect of radiation damage, the so called carrier removal (CR) requires additional consideration. Experimental measurements and numerical simulations reveal that with increasing radiation dose, CR can alter the initially quasi-intrinsic background doping of the MQW region to become further n or p type. This can result in a significant narrowing and even in a collapse of the electrical field between the emitter and the base where the MQWs are located. Eventually, remarks for improved radiation hard MQW device designs are provided.
