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Full-Text Articles in Nanoscience and Nanotechnology

Development Of High Band Gap Absorber And Buffer Materials For Thin Film Solar Cell Applications, Daniel Dwyer Jan 2011

Development Of High Band Gap Absorber And Buffer Materials For Thin Film Solar Cell Applications, Daniel Dwyer

Legacy Theses & Dissertations (2009 - 2024)

CuInGaSe2 (CIGS) device efficiencies are the highest of the thin film absorber materials (vs. CdTe, α-Si, CuInSe2). However, the band gap of the highest efficiency CIGS cells deviates from the expected ideal value predicted by models. Widening the band gap to the theoretically ideal value is one way to increase cell efficiencies. Widening the band gap can be accomplished in two ways; by finding a solution to the Ga-related defects which limit the open circuit voltage at high Ga ratios, or by utilizing different elemental combinations to form an alternative high band gap photoactive Cu-chalcopyrite (which includes …


Energy Band Engineering Using Polarization Induced Interface Charges In Mocvd Grown Iii-Nitride Heterojunction Devices, Neeraj Tripathi Jan 2011

Energy Band Engineering Using Polarization Induced Interface Charges In Mocvd Grown Iii-Nitride Heterojunction Devices, Neeraj Tripathi

Legacy Theses & Dissertations (2009 - 2024)

Characteristics of III-nitride based heterojunction devices are greatly influenced by the presence of high density of polarization induced interface charges. Research undertaken in the current doctoral thesis demonstrates the effect of presence of one, three and six sheets of polarization induced charges in three different III-nitride based devices, namely in a photocathode, a high electron mobility transistor (HEMT) and a hyperspectral detector structure. Through a systematic set of experiments and theoretical modeling an in-depth study of the interaction between multiple sheets of polarization induced charges and their impact on energy band profile was undertaken. Various device designs were studied and …


Effects Of Radiation-Induced Carbon Contamination On The Printing Performance Of Extreme Ultraviolet Masks, Yu-Jen Fan Jan 2011

Effects Of Radiation-Induced Carbon Contamination On The Printing Performance Of Extreme Ultraviolet Masks, Yu-Jen Fan

Legacy Theses & Dissertations (2009 - 2024)

This dissertation investigates one of the remaining issues for extreme ultraviolet (EUV) lithography, the effects of radiation induced carbon contamination on the printing performance of patterned EUV masks. The impact of carbon contamination on EUV masks is significant due to the throughput loss and potential effects on imaging performance, and occurs when multilayer surfaces are exposed to EUV radiation with residual carbonaceous species present. Current carbon contamination research is primarily focused on the lifetime of the multilayer surfaces, determined by reflectivity loss and reduced throughput in EUV exposure tools. However, contamination on patterned EUV masks can cause additional effects on …


Electron-Phonon Interactions And Quantum Confinement Effects On Optical Transitions In Nanoscale Silicon Films, Vimal Kumar Kamineni Jan 2011

Electron-Phonon Interactions And Quantum Confinement Effects On Optical Transitions In Nanoscale Silicon Films, Vimal Kumar Kamineni

Legacy Theses & Dissertations (2009 - 2024)

Theoretical studies have attributed the temperature dependence of the linear optical response (dielectric function) of bulk semiconductors to electron-phonon interactions and thermal expansion of the lattice. However, the role of phonons in the optical properties of nanoscale structures is often overlooked. This thesis systematically investigates the impact of both carrier confinement and electron-phonon interactions using nanoscale films of silicon in crystalline silicon quantum wells (c-Si QW). Spectroscopic ellipsometry (SE) is a linear optical technique used to of extract the dielectric function and thickness of very thin films. X-ray reflectivity (XRR) was used as the complementary thickness metrology method. The dielectric …


Applying X-Ray Microscopy And Finite Element Modeling (Fem) To Identify The Mechanism Of Stress-Assisted Void Growth In Through Silicon Via (Tsv), Lay Wai Kong Jan 2011

Applying X-Ray Microscopy And Finite Element Modeling (Fem) To Identify The Mechanism Of Stress-Assisted Void Growth In Through Silicon Via (Tsv), Lay Wai Kong

Legacy Theses & Dissertations (2009 - 2024)

Fabricating through-silicon vias (TSVs) is challenging, especially for conformally filled TSVs, often hampered by the seam line and void inside the TSVs. Stress-assisted void growth in TSVs has been studied by finite element stress modeling and X-ray computed tomography (XCT). Because X-ray imaging does not require TSVs to be physically cross-sectioned, the same TSV can be imaged before and after annealing. Using 8 keV laboratory-based XCT, voids formed during copper electroplating are observed in as-deposited samples and void growth is observed at the void location after annealing. We hypothesize that the mechanism generating voids is hydrostatic stress-assisted void growth. Stresses …


Synthesis, Processing And Characterization Of Silicon-Based Templated Nanowires, Jae Ho Lee Jan 2011

Synthesis, Processing And Characterization Of Silicon-Based Templated Nanowires, Jae Ho Lee

Legacy Theses & Dissertations (2009 - 2024)

Semiconductor and metallic nanowires have attracted substantial attention due to their wide variety of applications, ranging from nanoelectronics to energy storage devices. In particular, self-assembled silicon nanowires (SiNWs) may be an attractive alternative to conventionally processed planar silicon since SiNWs can potentially function as both the switch (i.e. transistor) and local interconnect (e.g. metal silicide nanowire) to form an inherently integrated nanoelectronic system. Also, hierarchical (branched) nanowire systems hold potential for catalysts or porous electrode applications for energy applications


Investigation Of Novel Alumina Nanoabrasive And The Interactions With Basic Chemical Components In Copper Chemical Mechanical Planarization (Cmp) Slurries, Shravanthi Lakshmi Manikonda Jan 2011

Investigation Of Novel Alumina Nanoabrasive And The Interactions With Basic Chemical Components In Copper Chemical Mechanical Planarization (Cmp) Slurries, Shravanthi Lakshmi Manikonda

Legacy Theses & Dissertations (2009 - 2024)

Chemical mechanical planarization (CMP) is an enabling process technology for IC fabrication to maintain global planarity across the wafer to satisfy lithographic depth of focus constraints. It also enables integration of materials that cannot be anisotropically etched, such as Cu. CMP utilizes nanoparticle abrasives in aqueous slurry to aid in planarization.


Effects Of Low Energy E-Beam Irradiation On Graphene And Graphene Field Effect Transistors And Raman Metrology Of Graphene On Split Gate Test Structures, Gayathri Rao Jan 2011

Effects Of Low Energy E-Beam Irradiation On Graphene And Graphene Field Effect Transistors And Raman Metrology Of Graphene On Split Gate Test Structures, Gayathri Rao

Legacy Theses & Dissertations (2009 - 2024)

Apart from its compelling performance in conventional nanoelectronic device geometries, graphene is an appropriate candidate to study certain interesting phenomenon (e.g. the Veselago lens effect) predicted on the basis of its linear electron dispersion relation. A key requirement for the observation of such phenomenon in graphene and for its use in conventional field-effect transistor (FET) devices is the need to minimize defects such as consisting of - or resulting from - adsorbates and lattice non-uniformities, and reduce deleterious substrate effects. Consequently the investigation of the origin and interaction of defects in the graphene lattice is essential to improve and tailor …