| Increasing the efficiency of solar cell technology is one of the current research aims being under taken in order to help supply growing global energy demands. The research presented in this thesis contributes to the current materials hunt for suitable candidates for an Intermediate Band Solar Cell (IBSC). A background on other "third generation" photovoltaic concepts along with details about the IBSC concept is also presented.;The research presented in this thesis contains theoretical and experimental work on a quantum dot (QD) nanostructure. The structure contains a GaAs substrate, followed by a 10 nm GaAs1-xSbx barrier, a single layer of InAs QDs, followed by another 10 nm GaAs1-xSbx barrier and then capped by a thick GaAs layer. Theoretical calculations that accounted for strain were performed for a range of Sb compositions (x=0.04, 0.12, 0.14, 0.18, 0.22, 0.26, 0.30), for a QD of modeled size of 40 nm x 40 nm x 5 nm (WxLxH) at 4.4 K.;Three samples containing the above structure were also studied by time integrated- and time resolved-photoluminescence. The samples had a 12% Sb concentration, but varied by their GaAs1-xSbx barrier thicknesses. Sample A had symmetric Sb barriers of 20 nm for the bottom and 20 nm for the top. Sample B had symmetric barriers of 10 nm for the bottom and 10 nm for the top, while sample C had asymmetric barriers of 30 nm for the bottom and 10 nm for the top. The samples were studied for temperature dependence for the range of 4.4 K to 300 K, and for excitation dependence from ∼3 W/cm2-225 W/cm2. |
