Fabrication and characterization of InAs/InGaAs sub-monolayer quantum dot solar cell with dot-in-a-well structure

• Published in: Current applied physics 2016, 16(5), , pp.587-592
• Main Authors: Han, Im Sik, Kim, Jong Su, Kim, Jun Oh, Noh, Sam Kyu, Lee, Sang Jun
• Format: Article
• Language: English
• Subjects: Carrier re-capturing and trapping; Carriers; Conversion; Dot-in-a-well structure; Electrical properties; Indium arsenides; Photovoltaic cells; Photovoltaic effect; Quantum dot solar cells; Quantum dots; Solar cells; Sub-monolayer; 물리학
• ISSN: 1567-1739; 1878-1675
• DOI: 10.1016/j.cap.2016.02.009

To improve the efficiency of InAs quantum dot solar cells (QDSCs), we propose a QDSC structure with sub-monolayer (SML) QDs. The optical and electrical properties of Stranski–Krastanow (SK) QDs and SML-QDs embedded in dot-in-a-well (DWELL) were investigated by photoluminescence and photoreflectance spectroscopy and illuminated J-V measurement. The SML-QDSC showed the improved probability of carriers thermally escaping from the QD states due to the small QD size. The suppression of carrier re-capturing enhanced the photovoltaic effect due to the enhanced carrier screening. The conversion efficiency of the SML-QDSC (η = 10.65%) was enhanced by about 12.58% compared to that of the SK-QDSC (η = 9.46%). The improved SC efficiency of the SML-QD is attributed to the suppressed carrier re-capturing and carrier trapping caused by the smaller QD size and lower defect density. •We report the optical and electrical properties of InAs/InGaAs sub-monolayer (SML) quantum dot (QD) solar cell.•SML-QD solar cell is compared with Stranski–Krastanow (SK) QD solar cell.•SML-QDs show the suppression of carrier re-capturing and trapping into QD states.•The conversion efficiency of SML-QD solar cell was enhanced about 12.58%.