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Sato, Shinichiro; Schmieder, K. J.*; Hubbard, S. M.*; Forbes, D. V.*; Warner, J. H.*; Oshima, Takeshi; Walters, R. J.*
Proceedings of 42nd IEEE Photovoltaic Specialists Conference (PVSC-42) (CD-ROM), 5 Pages, 2015/06
GaAs pn-junction diodes with embedded InAs quantum dots (QDs) are irradiated with protons and the generated deep level traps are investigated using Deep Level Transient Spectroscopy (DLTS). The results are compared to GaAs pn-junction diodes without QDs in order to identify the origin of the deep level traps. The fluence dependence of trap density is investigated, and it is shown that majority carrier traps induced by irradiation increase in proportion to the fluence whereas the EL2 trap, which appears before irradiation, is not affected by irradiation. In addition, minority carrier traps in the QD layer and electron/hole emission from QD levels are investigated by various reverse bias and pulse voltage conditions.
Sato, Shinichiro; Schmieder, K.*; Hubbard, S.*; Forbes, D.*; Warner, J.*; Oshima, Takeshi; Walters, R.*
no journal, ,
GaAs pn-junction diodes with embedded InAs quantum dots (QDs) are irradiated with high energy protons and the generated deep level traps are investigated using Deep Level Transient Spectroscopy (DLTS). The results are compared to GaAs pn-junction diodes without QDs in order to identify the origin of deep level traps. In addition, the fluence dependence of trap density is investigated and it is shown that traps induced by irradiation increase in proportion to the fluence whereas EL2 trap, which appears before irradiation, is not affected by irradiation.
n diodes embedded with InAs quantum dot layersSato, Shinichiro; Schmieder, K.*; Hubbard, S.*; Forbes, D.*; Warner, J.*; Oshima, Takeshi; Walters, R.*
no journal, ,
III-V semiconductor devices embedded with quantum dots (QDs) are expected to be applied to next generation space solar cells. High density QDs and highly stacked QD layers without stacking fault are required in order to relaize QD solar cells, and have been obtained recently by using strain compensating technology. However, larger amount of defects are still incorporated into QD devices compared to single crystal devices and affect the device characteristics. In this study, we fabricated GaAs pn diode with 10 layers of InAs QDs by Metal Organic Vapor Phase Epitaxy (MOVPE) method and characterized defect levels in the devices using Deel Level Transient Spectroscopy (DLTS). The results were compared to reference samples which were GaAs pn diodes without InAs QDs. It was shown that unique electron and hole trap levels were found in the QD devices and thus we concluded that these traps should be reduced in order to improve the device quality.
