Author: Hwa ChaoPublisher:
ISBN:
Category : Amorphous semiconductors
Languages : en
Pages : 81
Book Description
Preparation and Characterization of Hydrogenated Amorphous Silicon Films
Author: Hwa ChaoPublisher:
ISBN:
Category : Amorphous semiconductors
Languages : en
Pages : 81
Book Description
Characterization of Hydrogenated Amorphous Silicon Films
Author: Ernest Gerald BylanderPublisher:
ISBN:
Category :
Languages : en
Pages : 332
Book Description
Fabrication and Characterization of Hydrogenated Amorphous Silicon Films, CVD Diamond Films, and Their Devices
Author: Hao JiaGrowth Mechanisms and Characterization of Hydrogenated Amorphous- Silicon-alloy Films
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 17
Book Description
This report describes an apparatus, constructed and tested, that allows measurement of the surface morphology of as-grown hydrogenated amorphous silicon films with atomic resolution using a scanning tunneling microscope. Surface topologies of 100-[degree][Lambda]-thick intrinsic films, deposited on atomically flat, crystalline Si and GaAs, are reported. These films surfaces are relatively flat on the atomic scale, indicating fairly homogeneous, compact initial film growth. The effect of probe-tip size on the observed topology and the development of atomically sharp probes is discussed. 17 refs, 9 figs.
Preparation and Characterization of Hydrogenated Amorphous Silicon Thin Films and Thin Film Solar Cells Produced by Ion Plating Techniques. Final Report, 1 January 1979-31 May 1980
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Ion plating techniques for the preparation of hydrogenated amorphous silicon thin films have been successfully developed. The technique involves essentially the evaporation of elemental silicon through a d.c. produced hydrogen plasma. In this way hydrogen has been successfully incorporated into amorphous silicon films in concentrations as high as 30 atomic percent. Infrared spectroscopy indicates the usual SiHx stretching mode at approximately 2000 cm−1. Further evidence for the bonding of hydrogen was obtained from ESR measurement of hydrogenated and unhydrogenated samples. The measured unpaired spin density was a factor of 25 less in the hydrogenated sample. The optical absorption edges of the hydrogenated films fell in the usual range between 1.7 and 1.9 eV. Electrical conductivity measurements indicated a substantial reduction in the density of defect states in the gap as expected. It was also shown that hydrogenated amorphous silicon prepared by ion-plating could be doped by co-evaporation of the dopant element during film deposition. Both co-evaporated phosphorous and co-evaporated bismuth have been found to substantially increase the dark conductivity of a-Si:H while shifting the Fermi level towards the conduction band edge. An x-ray method for estimating the density and hydrogen content of a-Si:H has been developed. The measurement of strain in a-Si:H thin films is discussed. (WHK).
Atomic-scale Characterization of Hydrogenated Amorphous-silicon Films and Devices. Annual Subcontract Report, 14 February 1994--14 April 1995
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Properties of the hydrogenated amorphous silicon (a-Si:H) films used in photovoltaic (PV) panels are reported. The atomic-scale topology of the surface of intrinsic a-Si:H films, measured by scanning tunneling microscopy (STM) as a function of film thickness, are reported and diagnosed. For 1-500-nm-thick films deposited under normal device-quality conditions from silane discharges, most portions of these surfaces are uniformly hilly without indications of void regions. However, the STM images indicate that 2-6-nm silicon particulates are continuously deposited into the growing film from the discharge and fill approximately 0.01% of the film volume. Although the STM data are not sensitive to the local electronic properties near these particulates, it is very likely that the void regions grow around them and have a deleterious effect on a-Si:H photovoltaics. Preliminary observations of particulates in the discharge, based on light scattering, confirm that particulates are present in the discharge and that many collect and agglomerate immediately downstream of the electrodes. Progress toward STM measurements of the electronic properties of cross-sectioned a-Si:H PV cells is also reported.
Preparation and Characterization of Hydrogenated Amorphous Silicon Thin Films and Thin Film Solar Cells Produced by Ion Plating Techniques. Second Quarterly Progress Report, 1 April 1979-30 Jun 1979
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Using quartz substrates, hydrogenated a-Si thin films have now been produced both by flow discharge decomposition of silane and by the controlled ion plating of high purity silicon through flow discharges composed of silane, hydrogen, and argon using a modified Takagi apparatus. Thus far, thin films produced by both glow discharge decomposition of silane with and without magnetic confinement and by ion plating have been characterized and compared using x-ray diffractometry, infrared spectrometry, optical absorption spectroscopy and by their temperature dependence of resistivity. Based on these results, the ion plating technique of producing a-Si thin films looks extremely encouraging. Films have been produced at approximately ten times the decomposition rate obtained using glow discharge decomposition of silane, even with magnetic field containment. In addition the resulting thin film properties measured to date compare favorably with those obtained from glow discharge produced films.
Hydrogen Evolution and Crystallization in Hydrogenated Amorphous Silicon Films
Author: Nagarajan SridharGrowth Mechanisms and Characterization of Hydrogenated Amorphous- Silicon-alloy Films. Annual Subcontract Report, 14 February 1991--13 February 1992
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 17
Book Description
This report describes an apparatus, constructed and tested, that allows measurement of the surface morphology of as-grown hydrogenated amorphous silicon films with atomic resolution using a scanning tunneling microscope. Surface topologies of 100-°[Lambda]-thick intrinsic films, deposited on atomically flat, crystalline Si and GaAs, are reported. These films surfaces are relatively flat on the atomic scale, indicating fairly homogeneous, compact initial film growth. The effect of probe-tip size on the observed topology and the development of atomically sharp probes is discussed. 17 refs, 9 figs.
Atomic-scale Characterization of Hydrogenated Amorphous-silicon Films and Devices
Author: Publisher:
ISBN:
Category : Light
Languages : en
Pages : 0
Book Description
Our research is concerned with improving the electronic properties of hydrogenated amorphous silicon (a-Si:H) films and of photovoltaic (PV) cells that use these films. Two approaches toward this goal are being taken. One is to establish the character of silicon particle growth in the rf glow discharges that are used to make the films and PV cells, and to understand the particle incorporation into the films. The ultimate goal of this effort is to find mitigating techniques that minimize the particle incorporation. During this contract period, we have developed a novel particle light-scattering technique that provides a very detailed and sensitive diagnostic of the particles suspended in the discharge, The second program is directed toward measuring the electronic properties of these thin-film PV cells, as a function of depth within the cell. The approach being taken is to use a scanning tunneling microscope to measure the depth-dependent electronic properties of cross-sectioned PV cells. During the present period, cell cleaving and cross-section locating methods, both in a ultrahigh vacuum environment, have been successfully developed.