| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 77491 | Solar Energy Materials and Solar Cells | 2016 | 9 Pages |
•The effect of quantum dot (QD) size on the optical and electrical properties of InAs/GaAs QD solar cells (QDSCs) was investigated.•The QD size effects on the p-n junction electric fields (Fpn) and the efficiencies (η) of the QDSCs were revealed.•The QD size affects η and Fpn due to the balance between the carrier generation and exhaustion processes through trapping and re-capturing.
The effects of quantum dot (QD) size on the optical and electrical properties of InAs/GaAs QD solar cells (QDSCs) were investigated. QDSCs with varying InAs QD size were fabricated by controlling the total InAs deposition thickness (θ) from 0 to 3.0 mono-layers (ML). The optical and electrical properties of the QDSCs were investigated using photoluminescence (PL), time-resolved PL (TRPL), photoreflectance (PR) spectroscopy, capacitance-voltage (C-V), and current-voltage (J-V) measurements. The QD size effects on the p-n junction electric fields (Fpn) and the efficiencies (η) of the QDSCs were revealed. The QDSCs had a maximum η of 21.17% for θ=2.0 ML (the efficiency is enhanced by 17.4% over the reference GaAs-SC) and minimized Fpn (113 kV/cm) by an enhanced photovoltaic effect caused by improved carrier generation. We find that these optimal properties result from a balance between carrier generation and exhaustion processes through trapping and re-capturing by defects and relatively large QDs.
