We investigated the conduction- and valence-confined energy levels and first band-to-band transition energies of a type-II InAs/GaSb multi-quantum-well at 77 K and room temperature for various well and barrier thicknesses. We calculated the electron and hole confined energies based on Kane’s eight-band k.p formalism. We also explored the effect of the barrier width on the wells’ interactions, which was negligible for wells with a width wider than 30 nm. Moreover, we proposed a single exponential function to predict the first transition energies without considering the complex approach of k.p theory. Then, we measured the photoluminescence spectra of the manufactured samples, including thin wells (1, 2, and 3 monolayers) and wide barriers (50 nm). Finally, we made comparisons between the theoretical band-to-band transition energies for kz=0 and experimental results from the photoluminescence spectra for different well thicknesses at 77 and 300 K.

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In this experimental work, plasma treatment of the active layer in the bulk heterojunction solar cells was studied. The active layers consisting of zinc oxide nanoparticles:polyaniline were spin-coated on indium tin oxide covered glasses then kept in the cold plasma medium for different treatment times. The J-V characteristics were considered under air mass 1.5G standard illumination, and variations of the open-circuit voltages and short circuit currents were studied under different treatment times. The results show that there is an optimum treatment time to improve the properties of the layers. In order to understand the origin of this effect, the Hall coefficient, along with ultravioletvisible spectra were measured, and for studying the topological impact of plasma on the surface of the layers, atomic force microscopy and Fouriertransform infrared spectroscopy were considered. The measurements confirmed the time dependency of the open-circuit voltages and short circuit currents of the cells on the plasma treatment times. Atomic force microscopy of the layers shows the significant topological effects of the plasma treatments on the surface of the active layers for different treatment times. K E Y W O R D S hybrid solar cells, photovoltaic cells, plasma applications