To investigate the carrier generation, thermal escape, and recombination processes in the strain-balanced InGaAs/GaAsP multiple quantum well (MQW) structure into GaAs p-i-n solar cell, the frequency-dependent piezoelectric photothermal (PPT) method was adopted. Since the thermal diffusion length of the signal source decreases with increasing the chopping frequency, we investigated the depth profile of non-radiative recombination carrier loss. Two distinctive peaks were observed in the lower photon energy region below the bandgap of GaAs (Eg, 1.42 eV at RT) for the MQW structure inserted sample. They were caused by the excitonic absorption associated with the inter-subband transitions within the MQWs. Although PPT signal intensity at above the bandgap of GaAs decreased with increasing the chopping frequency, the signal intensity at MQW remained even at high frequency. These features are explainable in terms that photoexcited carriers thermally escape from MQW and diffuse to the GaAs substrate. Diffused carriers then recombine at GaAs substrate non-radiatively.
雑誌名
宮崎大學工學部紀要
巻
43
ページ
17 - 20
発行年
2014-07-31
出版者
宮崎大学工学部
Miyazaki University
Faculty of Engineering, University of Miyazaki
リポジトリのご案内
量子井戸太陽電池におけるキャリアの非発光再結合および輸送特性
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