Schematic layer structure of a QDSC grown on a GaAs (001) substrate with ten multistacks of InAs QDs embedded with strain-compensating spacer layers.
Cross-sectional STEM image of multistacked layers of InAs QDs embedded in 20-nm-thick strain-compensating spacer layers.
Projected current-voltage curves measured for QDSCs with varying thickness and nitrogen composition of strain-compensating spacer layer: (a) and , (b) and , (c) and , and (d) and , respectively. The net strain-balanced condition was achieved in all samples and the solar radiation was a simulated air-mass 1.5 spectrum at 1 sun.
Dependence of decrease in the open-circuit voltage (solid circle) of the QDSC and increase in the conduction-band offset at the heterointerface at both ends of the layer (solid line) as a function of nitrogen composition in . The schematic energy band structure of the QDSC is also shown in the inset.
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