691 research outputs found
Carius, L R, 414622
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/375964Surname: CARIUS. Given Name(s) or Initials: L R. Military Service Number or Last Known Location: 414622. Missing, Wounded and Prisoner of War Enquiry Card Index Number: 52761.256741
Item: [2016.0049.08272] "Carius, L R, 414622
CPM and PDS - A critical interpretation of expeimental results
No full textStiebig H, Siebke F, Carius R. CPM and PDS - A critical interpretation of expeimental results. Mat. Res. Soc. 1996;420:715
Structural and optoelectronic properties of microcrystalline silicon germanium
No full textKrause M, Stiebig H, Carius R, Zastrow U, Bay H, Wagner H. Structural and optoelectronic properties of microcrystalline silicon germanium. Journal of Non-Cryst. Solids. 2002;299-302:158-162
Optical properties of microcrystalline silicon determined by spectroscopic ellipsometry and photothermal deflection spectroscopy
No full textQuantum confinement and light trapping effects in nanoporous Ge
No full textSemiconductors containing nanopores have gained a renewed interest as they are able to adsorb and interact with atoms and molecules and can thus be used in several interesting and emerging applications. Ge film and bulk samples, self-implanted with Ge+ ions, have shown to have a sponge-like nanoporous structure [1], as shown in fig.1. Possible applications of porous semiconductors include various novel sensors, solar cells, optoelectronic devices; they can be used for catalysis, biological molecular isolation and purification or electrodes for micro-fuel cells [2 and reference therein].
Optoelectronic characterization of the layers are carried out by Surface Photovoltage (SPV) Spectroscopy, a powerful technique which allows for obtaining detailed information on material optical properties, such as electronic transitions at gap states, and band to band transitions [2,3]. In addition, structural and microscopic analyses have been carried out in order to identify amorphous or crystalline phases and the average size of the nano- pores. Different nanoporous (np) structures have been investigated: crystalline and amorphous np-Ge obtained by implantation of bulk Ge, as well as crystalline and amorphous np-Ge obtained by ion implantation of Ge film grown on Si substrates by molecular beam epitaxy and sputtering. The effect of Au nanoparticles embedded within the nanoporous structure has been also investigated.
Changes in the SPV spectra as a function of ion implantation fluence and annealing treatments have been found and discussed on the basis of the structural properties of the samples [4]. A significant enhancement of the SPV signal in np-Ge samples decorated with Au nanoparticles has been shown, and related to enhanced light trapping effects. SPV spectra of np-Ge thin films show the main peak, which corresponds to band-to-band transitions, significantly blue shifted with respect to the same peak in bulk np-Ge (fig.2). This result has been assigned to a quantum confinement effect occurring at Ge nano- walls separating the nanopores. In addition, a strong enhancement of the SPV signal has been observed due to light confinement effects. Quantum confinement and light trapping effects demonstrated in nanoporous Ge film deposited on Si substrate can be of major interest for future photovoltaic applications of thin film solar cells.
[1] G Impellizzeri et al Nanotechnology 23, 395604 (2012)
[2] D Cavalcoli et al Microporous and Mesoporous Mat 196, 175–178 (2014)
[3] L Kronik and Y. Shapira, Surf Sci Rep. 37,1 (1999)
[4] D Cavalcoli et al, in Semiconductors and Semimetals, Elsevier, (2015
Improvement of Open Circuit Voltage in Microcrystalline Silicon Solar Cells Using Hot Wire Buffer Layers
No full textMai Y, Klein S, Carius R, et al. Improvement of Open Circuit Voltage in Microcrystalline Silicon Solar Cells Using Hot Wire Buffer Layers. J. Non-cryst. Solids. 2006;352(9-20):1829-1831
More insights from CPM and PDS. Charged and neutral defects in a-Si:H
No full textSiebke F, Stiebig H, Carius R. More insights from CPM and PDS. Charged and neutral defects in a-Si:H. Solar Energy Materials and Solar Cells. 1997;49(1-4):7-12.CPM and PDS spectra of annealed and degraded a-Si:H are analyzed. Numerical simulations of CPM and PDS data using occupation statistics yield information on the energy distribution and the charge state of the defects. The simulations reveal the coexistence of charged and neutral defects resembling the predictions of the defect-pool model. Charged states dominate the defect densities of annealed and degraded a-Si:H. In the case of spatial homogeneous defect densities, different sensitivities of CPM and PDS on charged and neutral defects cause different defect absorptions detected by both methods. Spatially inhomogeneous defect densities caused, e.g. by voids or columnar growth are detected by combining CPM and PDS since PDS detects the total defect density while CPM favors regions with low defect densities
Defect distributions in a-Si(x)Ge(1-x): H
No full textCarius R, Stiebig H, Siebke F, Fölsch J. Defect distributions in a-Si(x)Ge(1-x): H. Journal of Non-Cryst. Solids. 1998;227-230:432-436.Gap states in a-SiGe:H alloys were examined by numerical simulations of sub-bandgap absorption spectra measured by the constant photocurrent method and photothermal deflection spectroscopy. In contrast to simple deconvolution methods our analysis uses occupation statistics and takes into account the condition of charge neutrality. The simulations yield information on the energy distribution and the charge state of the defects. The results reveal the coexistence of charged and neutral defects. The defect distributions are similar to those found in amorphous hydrogenated silicon. In the investigated range of compositions charged states dominate the defect density. Taking the position of the defect states as a reference level both band edges shift towards the defect states with decreasing band gap. In contrast to electron spin resonance measurements, no evidence for a distinction between Si-related and Ge-related defect states can be found in sub-bandgap absorption spectra. (C) 1998 Elsevier Science B.V. All rights reserved
Improved light absorption in thin-film silicon solar cells by integration of silver nanoparticles
No full textMoulin E, Sukmanowski J, Luo P, Carius R, Royer FX, Stiebig H. Improved light absorption in thin-film silicon solar cells by integration of silver nanoparticles. Journal of Non-Crystalline Solids. 2008;354(19-25):2488-2491.Silver nanoparticles, produced by thermal evaporation and a subsequent annealing treatment, were integrated at the back side of thin-film silicon solar cells. Metallic nanoparticles can lead to (i) a strong enhancement of the electric field in their surrounding when they are irradiated by light and (ii) significant scattering of the light when they have the proper diameter (>100 nm). In this study, we investigated the optical properties of two types of substrates, one with large and well separated ellipsoidal silver nanoparticles (with average lateral size of 300 nm), and the other with silver nanostructures connected to each other. Furthermore, these substrates were used as back reflectors in microcrystalline silicon solar cells in substrate (n-i-p) configuration. (C) 2007 Elsevier B.V. All rights reserved
Optical characteristics of intrinsic microcrystalline silicon
No full textJun KH, Carius R, Stiebig H. Optical characteristics of intrinsic microcrystalline silicon. Phys. Rev. B. 2002;66(11): 115301.We studied the optical properties of intrinsic microcrystalline silicon (muc-Si:H) deposited by very high frequency plasma-enhanced chemical-vapor deposition system at different silane concentrations (SC) by spectroscopy ellipsometry and photothermal deflection spectroscopy. The bulk property of the samples was probed because the impact of the surface layer was significantly reduced by mechanical polishing. At high SC, we extracted the optical characteristics of the disordered part by assuming a superposition of ideal c-Si and mathematically generated amorphous function. At low SC, we studied the reason for a large deviation of absorption coefficient in the energy range between 1.6 and 3.2 eV from the value predicted by effective medium theory. We considered the scattering loss by the inhomogeneity of muc-Si:H and introduce the dense medium radiative transfer formalism to an optical scattering simulation. We simulated the Stokes vector of p- and s-polarized light at oblique incidence. From this formalism, we could predict depolarization of p and s wave by scattered incoherent light. Further, we also suggested strain effect as the second possible reason for the enhanced absorption near the onset of the indirect transition in highly crystalline muc-Si:H
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