Reducing carrier escape in the InAs/GaAs quantum dot intermediate band solar cell
Reducing carrier escape in the InAs/GaAs quantum dot intermediate band solar cell
复制标题
DOI：
10.1063/1.3468520
复制
发表时间：
2010-09-15
影响因子：
3.2
通讯作者：
Luque, A.
中科院分区：
文献类型：
--
作者：
Antolin, E.;Marti, A.;Luque, A.
迄今为止，由 In (Ga)As/GaAs 量子点阵列 (QD-IBSC) 制造的中带太阳能电池 (IBSC) 表现出延伸至带隙能量以下的量子效率 (QE)。然而，亚带隙光电流的产生通常依赖于载流子从量子点的热逃逸和/或隧道逃逸，这与输出电压的保持不相容。在这项工作中，我们测试了在 QD 上除了 InAlGaAs 应变消除层 (SRL) 之外引入厚 GaAs 间隔物以减少载流子逃逸的有效性。通过对不同温度下 QE 的分析，得出的结论是，在短路条件下可以完全阻止通过隧道逃逸，并且用 InAlGaAs SRL 限制在 QD 中的载流子表现出比仅用 GaAs 封端的 InAs QD 的情况大 100 meV 以上的热逃逸激活能。 (C) 2010 年美国物理研究所。 [doi:10.1063/1.3468520]
Intermediate band solar cells (IBSCs) fabricated to date from In (Ga)As/GaAs quantum dot arrays (QD-IBSC) exhibit a quantum efficiency (QE) that extends to below bandgap energies. However, the production of sub-bandgap photocurrent relies often on the thermal and/or tunneling escape of carriers from the QDs, which is incompatible with preservation of the output voltage. In this work, we test the effectiveness of introducing a thick GaAs spacer in addition to an InAlGaAs strain relief layer (SRL) over the QDs to reduce carrier escape. From an analysis of the QE at different temperatures, it is concluded that escape via tunneling can be completely blocked under short-circuit conditions, and that carriers confined in QDs with an InAlGaAs SRL exhibit a thermal escape activation energy over 100 meV larger than in the case of InAs QDs capped only with GaAs. (C) 2010 American Institute of Physics. [doi:10.1063/1.3468520]