Download or read book Atomic scale Characterization of Hydrogenated Amorphous silicon Films and Devices written by and published by . This book was released on 1995 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atomic scale Characterization of Hydrogenated Amorphous silicon Films and Devices written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Atomic scale Characterization of Hydrogenated Amorphous silicon Films and Devices written by Alan C. Gallagher and published by . This book was released on 1997 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Atomic scale Characterization of Hydrogenated Amorphous silicon Films and Devices written by Alan C. Gallagher and published by . This book was released on 1998 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 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 mitigation techniques that minimize the particle incorporation. During this contract period, we developed a novel particle light-scattering technique that provides a detailed and sensitive diagnostic of small (8-60-nm diameter) particles suspended in the discharge. We used this to measure the particle growth rates and densities, versus conditions in pure-silane discharges. The second program is directed toward measuring the electronic properties of thin-film PV cells, as a function of depth within the cell. The approach being taken is to use a scanning tunneling microscope (STM) to measure the depth-dependent electronic properties of cross-sectioned PV cells. During the present period, measurements on single and tandem amorphous silicon cells have been carried out. Using STM current-voltage spectroscopy, these measurements distinguish the boundaries between the highly conducting and intrinsic layers, and should allow one to deduce the chemical potential versus depth in the cell.
Download or read book Publications of the National Institute of Standards and Technology Catalog written by National Institute of Standards and Technology (U.S.) and published by . This book was released on 1994 with total page 1162 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1995 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Growth Mechanisms and Characterization of Hydrogenated Amorphous silicon alloy Films Final Subcontract Report 15 February 1991 14 April 1994 written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes work performed to better understand the atomic-scale structure of glow-discharge-produced a-Si:H, a-Ge:H, and a-Si:Ge:H films; its effect on film quality; and its dependence on deposition discharge conditions. Hydrogenated a-Si films are from a silane rf discharge onto atomically flat crystal Si and GaAs substrates. The substrates are then transferred in a scanning tunneling microscope, where the atomic-scale surface morphology is measured. The films were deposited using device-quality deposition conditions; IR absorption, [sigma][sub L], and [sigma][sub D] indicate high-quality intrinsic films. From the thickness dependence of the surface morphology, we determined that the films initially conform smoothly to an atomically flat Si or GaAs substrate, but as the thickness increases the roughness steadily increases to approximately 10% of the length of the scanned region. The surface of 100--400-nm-thick films is highly inhomogeneous, with steep hills and canyons in some areas and large atomically smooth regions in others. These unexpectedly large surface irregularities indicate severe and often connected void structures in the growing film, as well as relatively limited-range surface diffusion of the incorporating SiH[sub 3] radicals. On the other hand, large atomically flat surface were occasionally found, indicating the possibility of growing a homogeneous and compact amorphous film if appropriate growth conditions could be discovered.
Download or read book Growth Mechanisms and Characterization of Hydrogenated Amorphous Silicon alloy Films Annual Subcontract Report 14 February 1991 13 February 1992 written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Growth Mechanisms and Characterization of Hydrogenated Amorphous silicon alloy Films Annual Subcontract Report 14 February 1992 13 February 1993 written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes work performed to better understand the atomic-scale structure of glow-discharge-produced a-Si:H, a Ge:H, and a-Si:Ge:H films; its effect on film quality; and its dependence on deposition discharge conditions. Hydrogenated a- Si films are deposited from a silane rf discharge onto atomically flat crystal Si and GaAs substrates. The substrates are then transferred in vacuum to a scanning tunneling microscope, where the atomic-scale surface morphology is measured. The films were deposited at T[sub s] = 30[degree]C and 250[degree]C from a silane rf glow discharge using device-quality deposition conditions of 2.66 Pa (0.5 Torr) silane pressure, 1.7 [Angstrom]/s deposition rate, and small power/flow; IR absorption, [sigma][sub L], and [sigma][sub D] indicate high-quality intrinsic films. From the thickness dependence of the surface morphology, we determined that the films initially conform smoothly to an atomically flat Si or GaAs substrate, but as the thickness increases the roughness steadily increases to approximately 10% of the length of the scanned region. The surface of 100-400-nm-thick films is highly inhomogeneous, with steep hills and canyons in some areas and large atomically smooth regions in others. These unexpectedly large surface irregularities indicate severe and often connected void structures in the growing film, as well as relatively limited-range surface diffusion of the incorporating SiH[sub 3] radicals. On the other hand, large areas of atomically flat surface were occasionally found, indicating the possibility of growing a homogeneous and compact amorphous film if appropriate growth conditions could be discovered.
Download or read book Growth Mechanisms and Characterization of Hydrogenated Amorphous silicon alloy Films written by Alan C. Gallagher and published by . This book was released on 1994 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synerjy written by and published by . This book was released on 1996 with total page 618 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1996 with total page 796 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Growth Mechanisms and Characterization of Hydrogenated Amorphous Silicon alloy Films written by and published by . This book was released on 1993 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Characterization of Hydrogenated Amorphous Silicon Films written by Ernest Gerald Bylander and published by . This book was released on 1988 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 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 written by and published by . This book was released on 1980 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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).
Download or read book Fabrication and Characterization of Hydrogenated Amorphous Silicon Films CVD Diamond Films and Their Devices written by Hao Jia and published by . This book was released on 1994 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preparation and Characterization of Hydrogenated Amorphous silicon Films Produced by Ion Plating and Hydrogenated Amorphous boron Films Produced by Glow Discharge Decomposition written by Franklin H. Cocks and published by . This book was released on 1981 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
