Structural Properties Of Deuterated Germanium Nitrogen Alloys

An infrared analysis of nonstoichiometric hydrogenated and deuterated germanium-nitrogen alloys is presented. The films were prepared by rf reactive sputtering of a c-Ge target in a gas mixture of Ar+N2+(H2 or D2). The isotopic effect was used to identify the absorption bands associated with the alloy elements bonded to hydrogen. Its infrared spectra pattern depends strongly on the preparation condition. Samples prepared in the 100-300°C temperature range are stable, while those prepared at temperatures lower than 100°C show spontaneous atmospheric contamination. In this case, the evolution of the infrared spectra with the atmosphere exposing time for hydrogenated and deuterated films was analyzed.76161561

Light induced electron spin resonance in a-Ge:H

We report the observation of light-induced electron spin resonance (LESR) in amorphous hydrogenated germanium. Two new lines with zero crossings near g=2.01 and g=2.03 were detected and ascribed to electrons and holes in the conduction- and valence-band-tail states, respectively. The ratio between the LESR spin densities of both lines is approximately one, suggesting the absence of spin pairing, charge defect creation, or LESR of dangling bonds. The growth and decay spectra exhibit dispersive behavior with a dispersion parameter ∼0.5. The decay spectrum is best fit assuming bimolecular recombination. The LESR spin density depends weakly on the photogeneration rate as a sublinear power law

Structure And Composition Of Amorphous Ge1-xsnx Thin Films

The composition and bonding configuration of amorphous germanium-tin (a-Ge1-xSnx) thin films are reported (0≤x<0.3). Mössbauer spectroscopy analyses show that under the reported deposition conditions all tin atoms enter the a-Ge network in a perfect substitutional way, i.e., in a covalent tetrahedral configuration. The absence of defect structures in the tin sites is discussed and compared with results on films prepared under different conditions.63115596559

Hard Hydrogenated Carbon Films With Low Stress

Analysis of hard a-C:H films with low stress prepared by methane plasma decomposition is reported. Films with hardness as high as 14 GPa and stress as low as 0.5 GPa were obtained. These films have a high Raman Id/Ig ratio (∼1.0), and small Tauc's band gap (∼0.4 eV). This letter also supplies strong evidence that the subimplantation deposition model, used to explain the formation of ta-C and ta-C:H films, is also valid for a-C:H films deposited by methane plasma decomposition. It is proposed that the rigidity of the films is basically provided by a matrix of dispersed cross-linked sp2 sites, in addition to the contribution of the sp3 sites. © 1998 American Institute of Physics.735617619Franceschini, D.F., Achete, C.A., Freire Jr., F.L., (1992) Appl. Phys. Lett., 60, p. 3229Chhowalla, M., Yin, Y., Amaratunga, G.A.J., McKenzie, D.R., Frauenheim, T., (1996) Appl. Phys. Lett., 69, p. 2344Hoffman, R.W., (1996) Physics of Thin Films, 3. , in edited by G. Hass and R. E. Thun Academic, New YorkJiang, X., Reichelt, K., Stritzker, B., (1989) J. Appl. Phys., 66, p. 5805Lifshitz, Y., Kasi, S.R., Rabalais, J.W., (1989) Phys. Rev. Lett., 68, p. 620Lifshitz, Y., Kasi, S.R., Rabalais, J.W., (1990) Phys. Rev. B, 41, p. 10468McKenzie, D.R., Muller, D., Pailthorpe, B.A., (1991) Phys. Rev. Lett., 67, p. 773Fallon, P.J., Veerasamy, V.S., Davis, C.A., Robertson, J., Amaratunga, G.A.J., Milne, W.I., Koskinen, J., (1993) Phys. Rev. B, 48, p. 4777Weiler, M., Sattel, S., Jung, K., Ehrhardt, H., Veerasamy, V.S., Robertson, J., (1994) Appl. Phys. Lett., 64, p. 2797Robertson, J., (1993) Diamond Relat. Mater., 2, p. 984Davis, C.A., (1993) Thin Solid Films, 226, p. 30Kohler, K., Coburn, J.W., Horne, D.E., Kay, E., (1985) J. Appl. Phys., 57, p. 59Chapman, B., (1980) Glow Discharge Process, , Wiley, New YorkMoller, W., (1993) Appl. Phys. A: Solids Surf., 56, p. 527Kleber, R., Weiler, M., Kruger, A., Sattel, S., Kunz, G., Jung, K., Ehrbardt, H., (1993) Diamond Relat. Mater., 2, p. 246Robertson, J., (1992) Phys. Rev. Lett., 68, p. 220Tamor, M.A., Vassell, W.C., Carduner, K.R., (1991) Appl. Phys. Lett., 58, p. 592Walters, J.K., Honeybone, P.J.R., Huxley, D.W., Newport, R., Howells, W.S., (1994) Phys. Rev. B, 50, p. 831Stephan, U., Frauenheim, T., Blaudeck, P., Jungnickel, G., (1994) Phys. Rev. B, 49, p. 1489Robertson, J., (1996) J. Non-Cryst. Solids, 198-200, p. 614Robertson, J., (1997) Diamond Relat. Mater., 6, p. 212Schwan, J., Ulrich, S., Batori, V., Ehrhardt, H., Silva, S.R.P., (1996) J. Appl. Phys., 80, p. 440Tamor, M., Vassel, W., (1994) J. Appl. Phys., 76, p. 446Prawer, S., Nugent, K.W., Lifshitz, Y., Lampert, G.D., Grossman, E., Kulik, J., Kalish, R., (1996) Diamond Relat. Mater., 5, p. 433Robertson, J., (1994) Pure Appl. Chem., 66, p. 1789Robertson, J., (1992) Surf. Coat. Technol., 50, p. 185Kelires, P.C., (1994) Phys. Rev. Lett., 73, p. 2460Amaratunga, G.A.J., Chhowalla, M., Kiely, C.J., Alexandrou, I., Devenish, R.M., (1996) Nature (London), 383, p. 32

Electrical Conductivity Of Amorphous Silicon Doped With Rare-earth Elements

This work reports on the electrical properties of a-Si samples doped with elements of the lanthanide series. A detailed study of gadolinium-doped a-Si is presented. It has been found that the introduction of rare-earth elements into the amorphous-silicon network produces large changes in the conductivity. An analysis of the experimental conductivity as a function of temperature and rare-earth content, together with the optical and electron-spin-resonance data, leads us to suggest that rare-earth-acceptor-like states located in the lower half of the pseudogap may be responsible for the measured properties. © 1991 The American Physical Society.43118946895

Effects Of Stress On Electron Emission From Nanostructured Carbon Materials

The electron field emission from a graphite like amorphous carbon film was investigated. Threshold fields as low as 8 V/νm were observed at an assisting energy of 400eV. The field emission characteristics of the films were explained in terms of the high sp2 concentration, and the high intrinsic compressive stress modifying the electronic band structure of the film/graphitic nanostructures.21417101714McKenzie, D.R., Muller, D., Pailthope, B.A., (1991) Phys. Rev. Lett., 67, p. 773Schwan, J., Ulrich, S., Theel, T., Roth, H., Ehrhardt, H., Becker, P., Silva, S.R.P., (1997) J. Appl. Phys., 82, p. 6024Lifshitz, Y., Kasi, S.R., Rabalais, J.W., Eckstein, W., (1990) Phys. Rev. B, 41, p. 10468Robertson, J., (1993) Diamond Relat. Mater., 2, p. 984Lacerda, R.G., Hammer, P., Lepienski, C.M., Alvarez, F., Marques, F.C., (2001) J. Vac. Sci. Technol. A, 19, p. 971Bhattacharyya, S., Subramanyam, S.V., (1997) Appl. Phys. Lett., 71, p. 632Kilic, C., Mehrez, H., Ciraci, S., (1998) Phys. Rev. B, 58, p. 7872Uher, C., Hockey, R.L., Ben-Jacob, E., (1987) Phys. Rev. B, 35, p. 4483Satyanarayana, B.S., Hart, A., Milne, W.I., Robertson, J., (1997) Appl. Phys. Lett., 71, p. 1430Carey, J.D., Forrest, R.D., Silva, S.R.P., (2001) Appl. Phys. Lett., 78, p. 2339Illie, A., Ferrari, C., Yagi, T., Robertson, J., (2000) Appl. Phys. Lett., 76, p. 2627De Lima M.M., Jr., Lacerda, R.G., Vilcarromero, J., Marques, F.C., (1999) J. Appl. Phys., 86, p. 4936Hoffman, R.W., (1966) Physics of Thin Films, 3, pp. 211-273. , edited by G. Hass and R. E. Thun (Academic, New YorkCarey, J.D., Silva, S.R.P., (2001) Appl. Phys. Lett., 78, p. 347Hammer, P., Victoria, N.M., Alvarez, F., (2000) J. Vac. Sci. Technol. A, 18, p. 2277Lifshitz, Y., Lempert, G.D., Grossman, E., Avigal, L., Uzan-Saguy, C., Kalish, R., Khlik, J., Rabalais, J.W., (1995) Diamond Relat. Mater., 4, p. 318Fallon, P.J., Veerasamy, V.S., Davis, C.A., Robertson, J., Amaratunga, G.A.J., Milne, W.I., Koskinen, J., (1993) Phys. Rev. B, 48, p. 4777Ahuja, R., Auluck, S., Trygg, J., Wills, J.M., Eriksson, O., Johansson, B., (1995) Phys. Rev. B, 51, p. 4813Reynolds, W.N., Goggin, P.R., (1960) Philos. Mag., 5, p. 1049Lynch, R.W., Drickamer, H.G., (1966) J. Chem. Phys., 44, p. 181Chaumet, P.C., Dufour, J.P., (1998) J. Electrost., 43, p. 145Hryd, R., Charlier, A., McRae, E., (1997) Phys. Rev. B, 55, p. 682

Mössbauer Study Of Hydrogenated Amorphous Germanium-tin Thin-film Alloys

This work reports on the structure of defects around Sn atoms in amorphous germanium-tin alloys deposited by the rf sputtering of compound targets. The influence of atomic hydrogen on the structure of such defects is reported for the first time. The samples were analyzed by Rutherford backscattering spectrometry and conversion electron Mössbauer spectroscopy. The main conclusion of this research is that, besides the known substitutional position of Sn atoms in the a-Ge network, a new Sn bonding configuration appears, which may be at the origin of the degradation of the optoelectronic properties of the alloy found experimentally. This new configuration is an octahedrally coordinated Sn atom resulting from the trapping of Ge vacancies by Sn atoms, the energetically favored final site being the tin atom in the center of the Ge relaxed divacancy.6652083209

Electron Spin Resonance In Amorphous Silicon Doped With Gd

ESR experiments on Gd impurities in amorphous silicon between liquid-He and room temperatures show three resonances which could be ascribed to paramagnetic dangling bonds (g=2.00550.0005), to Gd S7/28 states (g=1.9970.005), and to a new paramagnetic center (g=2.100.05) associated with the presence of Gd atoms. For low-Gd-concentration samples the intensity of the resonance due to dangling bonds decreases as the Gd concentration increases and the intensity of the new paramagnetic center is found to increase with increasing temperature. These results indicate, as we recently found for other rare-earthelement impurities in a-Si, that a fraction of the Gd atoms act as acceptor impurities with associated loosely bound holes in the a-Si valence-band tail which are responsible for the resonance of the new paramagnetic center observed at a g value of 2.100.05. © 1989 The American Physical Society.39128398840

New Paramagnetic Center In Amorphous Silicon Doped With Rare-earth Elements

A new paramagnetic center associated with rare earths (RE) (La, Ce, Pr, Nd, Gd, Er, and Lu) in amorphous silicon is reported. It is shown that RE impurities are incorporated in a-Si and that the density of paramagnetic dangling bonds decreases as a consequence of the presence of these impurities. An interpretation in terms of RE 6s orbitals and crystal-field-split 5d orbital hybridization suggests that the RE behaves as an acceptor impurity with an associated hole in the a-Si valence-band tail, which is responsible for the observed resonance at a g value of 2.100.01. © 1989 The American Physical Society.3942860286

Perspectivas de penetração da energia solar fotovoltaica descentralizada no mercado português

CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMO: A tecnologia solar fotovoltaica (PV) tem assumido um papel central na narrativa portuguesa em atingir a neutralidade carbónica em 2050, com destaque para fontes electroprodutoras distribuídas. No Roteiro para Neutralidade Carbónica 2050 apresentado pelo governo português, o solar PV descentralizado atinge um potencial de 13 GW baseado numa metodologia da Agência Internacional de Energia (IEA). A partir disto, o presente trabalho faz um estudo aprofundado da capacidade técnica do solar PV distribuído fundamentado em diferentes modelos de cálculo da IEA, explora a disponibilidade de área de cobertura, e a viabilidade económica da tecnologia nas tipologias residencial, comercial e industrial em diversas regiões portuguesas. Avalia-se que há possibilidade técnica de ultrapassar a projeção de 13 GW, tanto pela área existente quanto pelos métodos distintos da IEA, e verifica-se que o investimento em sistemas PV é mais rentável para consumidores comerciais e industriais do que para domésticos. Incentivos fiscais impulsionariam o solar PV descentralizado, para além dos sistemas com baterias que são atualmente pouco acessíveis.ABSTRACT: Solar photovoltaic (PV) technology has taken on a pivotal role in the Portuguese effort to achieve carbon neutrality in 2050 with an emphasis on distributed power generating sources. In the Carbon Neutrality Roadmap 2050 presented by the Portuguese government, decentralised solar PV reaches a potential of 13 GW based on the International Energy Agency’s (IEA) methodology. Following this, the present study carries out a thorough analysis of the distributed solar PV technical capacity based on different IEA models, explores the availability of solar roof area and conducts a feasibility study of the technology in the residential, commercial and industrial typologies in several Portuguese regions. Analyses show that it is technically possible to exceed the 13 GW forecast, both by the existing roof area and by the distinct IEA methods. Furthermore, calculations indicate that it is more profitable to invest in PV systems for commercial and industrial consumers than for domestic ones. Tax incentives would boost decentralised solar PV, in addition to systems with battery storage that are, at present, hardly affordable.info:eu-repo/semantics/publishedVersio