Work function of few layer graphene covered nickel thin films measured with Kelvin probe force microscopy

Few layer graphene and graphite are simultaneously grown on a similar to 100 nm thick polycrystalline nickel film. The work function of few layer graphene/Ni is found to be 4.15 eV with a variation of 50 meV by local measurements with Kelvin probe force microscopy. This value is lower than the work function of free standing graphene due to peculiar electronic structure resulting from metal 3d-carbon 2p(pi) hybridization. (C) 2016 AIP Publishing LLC

Formation of the physical vapor deposited CdS Cu In,Ga Se2 interface in highly efficient thin film solar cells

We report on the buffer absorber interface formation in highly efficient 14.5 , AM1.5 ZnO CdS Cu In,Ga Se2 solar cells with a physical vapor deposited CdS buffer. For Se decapped Cu In,Ga Se2 CIGSe absorbers we observe sulfur passivation of the CIGSe grain boundaries during CdS growth and at the interface a thermally stimulated formation of a region with a higher band gap than that of the absorber bulk, determining the height of the potential barrier at the CdS CIGSe interface. For air exposed CIGSe samples the grain boundary passivation is impeded by a native oxide adsorbate layer at the CIGSe surface determining the thermal stability of the potential barrier heigh

Dopant imaging of power semiconductor device cross sections

Several Scanning Probe Microscopy (SPM) methods allow to image dopant profiles in a range from 10(14) cm(-3) to 10(19) cm(-3) on semiconducting samples. In our work we present Scanning Capacitance Force Microscopy (SCFM) and Kelvin Probe Force Microscopy (KPFM) experiments performed on cross sections of silicon (Si) and silicon carbide (SiC) power devices and epitaxially grown calibration layers. The contact potential difference (CPD) shows under illumination a reduced influence on surface defect states. In addition results from numerical simulation of these microscope methods are discussed. (C) 2016 Elsevier B.V. All rights reserved