Determination of the transport parameters of nanocrystalline CdSe:Cu thin films

Abstract

Thin films of copper (Cu)-doped CdSe are prepared by the physical vapor deposition technique. X-ray diffraction analysis shows that the films crystallize in hexagonal structure with (100) as the preferred orientation. Scanning electron microscope studies reveal that the grains are spherical in shape and uniformly distributed all over the surface of the substrates. The transport properties of Cu-doped CdSe thin films have been investigated by the time-of-flight measurement, steady-state photocarrier grating and steady-state photoconductivity techniques. The temperature dependence of dark conductivity and photoconductivity data reflects the existence of two independent donor energy levels. The bimolecular recombination nature of the thin films has been found from the photocurrent-illumination dependence at different applied voltages. The minority carrier diffusion length (L diff ) is obtained both from the best fit of the experimental photocurrent ratio β versus grating period ( ) and from the 'Balberg plot'. A straight line has been obtained from the best fit, which confirms that the measured length is the ambipolar diffusion length.

Progress in Plasmonic Enhanced Bulk Heterojunction Organic/Polymer Solar Cells

“…As discussed in previous sections, plasmonic structures improve the absorption efficiency of the photovoltaic absorber layers by preferentially scattering [40] and exciting localized surface plasmons [12,41] or plasmon polaritons [42][43][44][45][46]. Surface plasmons are localized by noble metallic nanoparticles (NPs) such as Cu [47][48][49], Ag and Au; resulting in localized surface plasmon resonance (LSPR). Ag and Au NPs are the most widely used materials due to their surface plasmon resonances located in the visible range.…”

Influence of Zn doping on structural, optical and electrical properties of nanocrystalline CdSe thin films

“…In recent years, much effort has been devoted to the research of doped metal chalcogenide nanostructured materials [17][18][19][20][21]. The electronic and optical properties of semiconductors are strongly influenced by the methods of preparation and doping process, which provides the basis for tailoring the desired carrier concentration and consequently the absorption, emission and transport properties.…”