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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Thickness dependence and doping effect on transport properties of post-hydrogenated amorphous silicon films prepared by vacuum evaporation.

January 1988 (has links)
by Ho Wai Hung. / Thesis (M.Ph.)--Chinese University of Hong Kong, 1988. / Bibliography: leaves 81-83.
12

Growth, doping and nanostructures of gallium nitride

Cai, Xingmin. January 2005 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.
13

Improved understanding and control of Mg-doped GaN by plasma assisted molecular beam epitaxy

Burnham, Shawn David. January 2007 (has links)
Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008. / Doolittle, W. Alan, Committee Chair ; Ferguson, Ian T., Committee Member ; Cressler, John D., Committee Member ; Dorsey, John F., Committee Member ; Carter, W. Brent, Committee Member.
14

Encapsulation of Si:P devices fabricated by scanning tunnelling microscopy

Goh, Kuan Eng Johnson, Physics, Faculty of Science, UNSW January 2006 (has links)
This thesis demonstrates the effective use of low temperature molecular beam epitaxy to encapsulate planar Si:P (phosphorus-in-silicon) devices lithographically patterned by scanning tunnelling microscopy (STM) without significant redistribution of the dopants. To achieve this goal, low temperature magnetotransport is used in combination with STM, Auger electron spectroscopy and secondary ion-mass spectrometry to analyse Si:P ??-doped samples fabricated under different doping and growth conditions. An important aspect of this project is the use of large 1 ?? 1 cm2 Si(001) samples which are about five times larger than standard STM samples. The larger sample size is necessary for post-STM fabrication lithography processes in a cleanroom but presents problems for preparing atomically clean surfaces. The ability to prepare clean and atomically flat Si(001) surfaces for STM lithography on such 1 ?? 1 cm2 samples is demonstrated, and it is shown that Si:P ??-doped layers fabricated on these surfaces exhibit complete electrical activation. Two dopant sources (gaseous PH3 and solid GaP source) were investigated to assess their compatibility with STM-lithography on the H:Si(001) surface. The findings show that while the PH3 and GaP sources result in near identical electrical qualities, only PH3 molecules are compatible with H-resist based lithography for controlled nano-scale doping. For achieving complete activation of the P dopants, it is shown that an anneal to ??? 350 ???C to incorporate P atoms into the Si surface prior to encapsulation is critical. While it is known that the presence of H during growth degrades the quality of Si epitaxy, investigations in this thesis indicate that it has no significant effect on dopant activation. Systematic studies performed to assess the impact of growth temperature recommend an encapsulation temperature of 250 ???C for achieving optimal electrical qualities with minimal dopant segregation. In addition, it is shown that rapid thermal anneals (RTAs) at temperatures &lt 700 ???C provide only marginal improvement in the electrical quality of Si:P ??-doped samples encapsulated at 250 ???C, while RTA temperatures &gt 700 ???C should be avoided due to the high probability of dopant redistribution. To elucidate the nature of 2D transport in Si:P ??-doped devices, a detailed analysis of the low temperature magnetotransport for Si:P ??-doped layers with doping densities in the range ??? 0.2 ??? 2 ?? 1014 cm???2 was carried out. Using conventional 2D theories for disordered systems, both weak localisation (WL) and electron-electron interactions (EEI) are shown to contribute almost equal corrections to the 2D conductivity. In particular, it is found that EEI can introduce a significant correction in the Hall coefficient RH (hence Hall density) especially in the low density/temperature regime and the need to correct for this when using the Hall density to estimate the activated electron density is highlighted. While the electronic mean free path in such highly doped ??-layers is typically &lt 10 nm making ballistic transport in these devices difficult to observe, the phase coherence length can extend to almost 200 nm at about 0.3???0.5 K for doping densities of ??? 1 ??? 2 ?? 1014 cm???2. Finally, the optimised encapsulation strategy developed in this thesis is applied to a 2D square device fabricated by STM. The device exhibits Ohmic conductivity with complete dopant activation. An analysis of its low temperature magnetotransport shows that the device behaves similarly to a Si:P ??-doped layer encapsulated under similar conditions, thus highlighting that the STM patterning process had no adverse effect on device quality.
15

Surface reactions, hydride kinetics and in situ boron doping of silicon and germanium /

Gong, Bin, January 1999 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 167-175). Available also in a digital version from Dissertation Abstracts.
16

Growth kinetics and doping of gallium nitride grown by RF-plasma assisted molecular beam epitaxy

Ptak, Aaron J. January 2001 (has links)
Thesis (Ph. D.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains xvii, 161 p. : ill. Includes abstract. Includes bibliographical references (p. 154-161).
17

Diffusion of sulfur into natural diamond : characterization and applications in radiation detection /

West, Matthew K. January 1999 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references (leaves 120-124). Also available on the Internet.
18

Studies of structures, transport and magnetic properties of doped novel three-dimensional perovskite compounds

Farhoudi, Mohammad Mehdi. January 2009 (has links)
Thesis (Ph.D.)--University of Wollongong, 2009. / Typescript. Includes bibliographical references: leaf 174-191.
19

FP-LMTO modeling of ZnSe and ZnMgSe alloy

Yang, Yaxiang. January 2001 (has links)
Thesis (Ph. D.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains viii, 113 p. : ill. (some col.). Includes abstract. Includes bibliographical references.
20

Diffusion of sulfur into natural diamond characterization and applications in radiation detection /

West, Matthew K. January 1999 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references (leaves 120-124). Also available on the Internet.

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