Fabrication of 100 layer-stacked InAs/GaNAs strain-compensated quantum dots on GaAs (001) for application to intermediate band solar cell

Abstract

In order to demonstrate the predicted high efficiency operation of a quantum dot intermediate band solar cell (QD-IBSC), high-density QD superlattice with good size homogeneity is required. Though multiple stacking is one promising way to increase the total QD density thereby increasing the optical absorption by QD-IB, it is difficult to maintain the size homogeneity and structural quality of QD superlattice. For this, we take advantage of strain-compensation growth technique, in which the compressive strain induced by each InAs QD layer is compensated, or balanced out, by embedding it with a tensile-strained GaNAs strain-compensating layer. In this work, we demonstrate a high quality growth of up to 100 layer-stacked InAs/GaNAs QD superlattice on GaAs (001) substrate. We have also characterized some basic solar cell characteristics.