Multi-stacked quantum dots with graded dot sizes for photovoltaic applications

Multiple stacks of quantum dots are proposed as an active layer in a novel solar cells structure. A simple growth technique reported here proves to be an important enabling technology, making uniform, controllable stacks of InAs dots. Schottky solar cells fabricated from the multi-stacked graded dots wafer show current-voltage characteristics which indicate a significant improvement in short-circuit current when compared to the same devices fabricated from a non-graded dots wafer. Spectral response at 1.0-1.4 μm region is attributed to the quantum dot layers.