Field-Dependent Characteristics of Two-Step Photoexcited Current Generation in a Quantum-Dot Superlattice Solar Cell

• KADA Tomoyuki

  Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University

• ASAHI Shigeo

  Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University

• HARADA Yukihiro

  Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University

• KITA Takashi

  Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University

Bibliographic Information

Other Title

• 量子ドット超格子太陽電池における2段階光励起電流生成ダイナミクスの電界依存特性
• リョウシ ドット チョウコウシ タイヨウ デンチ ニ オケル 2 ダンカイ ヒカリレイキデンリュウ セイセイ ダイナミクス ノ デンカイ イソン トクセイ

Abstract

We studied effects of the internal electric field on the two-step photocurrent generation in quantum dot superlattice (QDSL) solar cells. We calculated the quantum efficiency of intersubbad photoexcited carriers in QDSL as a function of the internal electric field. In our calculation, we proposed a model of a QDSL structure in which electrons created by the interband transition are excited by subbandgap photons corresponding to the intersubband transition. We found that extra photocurrent caused by the two-step photoexcitation shows the maximum at a reverse biased electric field, whereas current generated by only the interband photoexcitation increases monotonically with increasing the electric field. The internal electric field of the solar cell can separate photocreated electron and hole in the SL miniband, and electron lifetime is extended, which improve the intersubband transition strength, and, therefore, the two-step photocurrent increases. Thus, the calculated result unveils that there is a trade-off relation between carrier separation in the SL miniband and electric-field induced carrier escape from QDSL. These results clarify that long electron lifetime extended by carrier separation is a key maximizing the two-step photocurrent generation in a QDSL solar cell.

Journal

• Journal of the Society of Materials Science, Japan

  Journal of the Society of Materials Science, Japan 65 (9), 647-651, 2016

  The Society of Materials Science, Japan

Keywords

• Solar cell
• Quantum dot
• Super lattice
• Miniband
• Photocurrent
• Intersubbnad photoexcitation
• Electric field

Details

• CRID: 1390282680421004416
• NII Article ID: 130005416082
• NII Article ID: 40020960442
• NII Book ID: AN00096175
• DOI: 10.2472/jsms.65.647
• ISSN: 18807488
• ISSN: 05145163
• NDL BIB ID: 027655978
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I027655978
• Web Site: https://www.jstage.jst.go.jp/article/jsms/65/9/65_647/_pdf
• Text Lang: ja
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed