16 March 2015 Extreme broadband photocurrent spectroscopy on InAs quantum dot solar cells
Author Affiliations +
Intermediate band solar cell (IBSC) is a promising concept to achieve next generation high-efficiency solar cells by producing the gain in photocurrent via two-step photon absorption while preserving the output voltage as of the host materials. Quantum dot (QD) superlattice is a widely studied candidate to implement the IB in real devices. In this paper, a missing transition from the IB to the conduction band (CB) has been investigated by applying extreme broadband photocurrent spectroscopy extended to mid-infrared (IR) region. In both direct and delta Si-doped InAs QDSCs, photocurrent signals were observed at the short-circuit condition at low temperature solely with sub-bandgap mid-IR photo-irradiation. On the other hand, in an undoped QDSC, no significant signal was obtained. Furthermore, the mid-IR signal was reduced by decreasing the modulation frequency and turned to be zero at DC detection. We ascribe this to the displacement photocurrent by the inter-subband transition of thermal equilibrium carriers in QDs.
© (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
R. Tamaki, R. Tamaki, Y. Shoji, Y. Shoji, S. Naitoh, S. Naitoh, Y. Okada, Y. Okada, K. Miyano, K. Miyano, } "Extreme broadband photocurrent spectroscopy on InAs quantum dot solar cells", Proc. SPIE 9358, Physics, Simulation, and Photonic Engineering of Photovoltaic Devices IV, 93580V (16 March 2015); doi: 10.1117/12.2081084; https://doi.org/10.1117/12.2081084

Back to Top