Characterization of a quantum dot nipi photovoltaic device

Quantum dot nipi test structures consisting of n-type / intrinsic / p-type / intrinsic layers have been developed to probe the effects of placing quantum dots within a doping superlattice. Coupling between the doping superlattice states and quantum dots that can be grown within the superlattice results in increases in carrier lifetimes within the quantum dots, and modifies the absorption spectrum. With the addition of dots within a nipi device, the benefits have been quantified by measuring absorption, activation energy, photoluminescence, and lifetime. By characterizing the modified quantum dot properties, it is hopeful that this will demonstrate the potential of the nipi structure as an intermediate band solar cell candidate.