Two-step photocurrent generation enhanced by the fundamental-state miniband formation in intermediate-band solar cells using a highly homogeneous InAs/GaAs quantum-dot superlattice. (30th November 2017)

• Record Type: Journal Article
• Authors: Hirao, Kazuki; Asahi, Shigeo; Kaizu, Toshiyuki; Kita, Takashi
• Is Part Of: Applied physics express. Volume 11:Number 1(2018)
• Publication Date: 2017-11-30
• Subjects: Physics -- Periodicals; Technology -- Periodicals; 621.05
• DOI: 10.7567/APEX.11.012301
• Languages: English
• ISSNs: 1882-0778

Abstract

Abstract: We studied intermediate-band solar cells (IBSCs) incorporating highly homogeneous InAs/GaAs quantum dot superlattices (QDSLs). The extra photocurrent generated by two-step photon absorption markedly increases at the fundamental state (FS) because the FS miniband has been successfully formed in the QDSL-IBSC by controlling the QD size homogeneity. Here, the carriers excited into the miniband spatially separate in the internal electric field, and the long-lived electrons in the intermediate states of the miniband increase the inter-subband absorption strength. The two-step photocurrent response, therefore, extends toward the longer-wavelength side corresponding to the QDSL-FS at approximately 1.2 µm.