Effect of space layer doping on photoelectric conversion efficiency of InAs/GaAs quantum dot solar cells

Journal Article · Mon Nov 16 04:00:00 EST 2015 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4935940· OSTI ID:22486103

Lee, Kyoung Su; Lee, Dong Uk; Choi, Won Jun ^[1]

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1. Center for Opto-Electronic Convergence Systems, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of)

We report an effect of photoelectric conversion efficiency (PCE) by space layer doping in InAs/GaAs quantum dot solar cells (QDSC) and δ-doped QDSC grown by molecular beam epitaxy. The PCEs of QDSC and δ-doped QDSC without anti-reflection coating were 10.8% and 4.3%, respectively. The QDSC had about four electrons per QD, and its ideality factor was temperature-independent, which implies that recombination of electron-hole pairs is suppressed by strong potential barriers around charged dots. From the deep level transient spectroscopy measurements, four defect levels, including QD with the activation energy ranges from 0.08 eV to 0.50 eV below GaAs conduction band edge, appeared. Especially, the M1 defect (E{sub c}-0.14 eV) was newly formed in δ-doped QDSC and its density was higher than those of M3 (E{sub c}-0.35 eV) and M4 (E{sub c}-0.50 eV) levels in QDSC. These results suggest that the photo-carriers recombining at M1 defect might be responsible for the reduction of PCE in δ-doped QDSC.

• OSTI ID: 22486103
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 20 Vol. 107; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACTIVATION ENERGY
CARRIERS
CONVERSION
DEEP LEVEL TRANSIENT SPECTROSCOPY
DOPED MATERIALS
EFFICIENCY
EV RANGE
GALLIUM ARSENIDES
HOLES
INDIUM ARSENIDES
LAYERS
MOLECULAR BEAM EPITAXY
POTENTIALS
QUANTUM DOTS
SOLAR CELLS