Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 21 for “"Fermi level pinning"”.
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Electrical contacts on two-dimensional transition metal dichalcogenide semiconductors
… However, unusually high contact resistance and Fermi level pinning have been observed due to damage at the metal-2D TMD interface. Studies have shown that van der Waals (vdW) contacts formed by dry transfer of graphene and metals can avoid damage to atomically thin TMDs caused by metal …
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Elektrischer Transport in GaN- und InN-Nanodrähten
… bending at the edge of the wires caused by the fermi level pinning inside the forbidden band. This model can be fit to the data with the three parameter doping, fermi level pinning and wire diameter. On the base of those effects a method to determine the doping concentration inside those wires …
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Two-dimensional Electronics: From Material Synthesis to Device Applications
… graphene on various insulating substrates; (2) Fermi level pinning observed in TMDs and integration of graphene contact to lower the contact resistance; and (3) application of metal-insulator-semiconductor (MIS) contact in TMD field-effect transistors (FETs). First, a direct low-temperature …
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Density Functional Simulations of Defect Behavior in Oxides for Applications in MOSFET and Resistive Memory
… results in the literature. In chapter 5, the Fermi level pinning effect is explored for metal semiconductor electrical contacts in Ge MOSFETs. It is found that germanides show much weaker Fermi level pinning than normal metal on top of Ge, which is well explained by the interfacial dangling …
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Material and device aspects of semiconducting two-dimensional crystals
… transistors and silicon MOSFET, and 3) circuit-level integration of devices using 2D semiconductors. A direct atomic layer deposition process was developed and investigated on various 2D crystals which allowed for the development of 2D semiconductor transistors. N-type MoS<sub>2</sub> …
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Phase-Engineered Field-Effect Transistors Based on Two-Dimensional Transition Metal Dichalcogenides
… schottky barrier height resulting from strong fermi-level pinning and the existence of van der Waal gaps at the metal/TMDC interface and in-between TMDC layers. The ultimate solution to the contact issue is to utilize lateral metallic-semiconducting TMDC junctions as 2D edge contacts. Thanks to …
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Dipole Contact Engineering for Field-Effect Transistors Based on Two-Dimensional Materials
… van der Waals surface of 2D materials and the Fermi level pinning effect. A variety of methods have been explored to make ohmic contacts to MoS₂, the most promising of which so far is to use semimetals such as Bi and Sb, however these materials suffer from thermal instability. This thesis …
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Study of surface modifications for improved selected metal (II-VI) semiconductor based devices.
… the metal used; for [mathematical formula]. Deep levels measured within this study and those reported in the literature led to the conclusion that Fermi level pinning by native defects is a dominant mechanism in Schottky barrier formation in these systems.
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Modeling The Atomic And Electronic Structure Of Metal-Metal, Metal-Semiconductor And Semiconductor-Oxide Interfaces
… MD and DFT transport calculations. Strong Fermi Level Pinning (FLP) is seen at these interfaces independent of doping concentrations</p> <p>providing theoretical support for the Metal-Induced Gap States (MIGS) model in describing FLP at Metal-Si interfaces.</p> <p>A DFT reaction pathway …
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Electronic structure, defect formation and passivation of 2D materials
… but the slope does not always equal because Fermi level pinning (FLP) arises. The chemical trend of FLP is investigated. Then we show that the pinning factor of Si can be tuned by inserting an oxide interlayer, which is important in the application to dopant-free Si solar cells. Apart from …
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Photovoltaic properties and size-pH phase stability of iron disulfide from density-functional theory
… devices. Two widely-accepted causes are: (i) Fermi level pinning caused by intrinsic surface states that appear as gap states; (ii) presence of the polymorph marcasite. Based on density-functional theory (DFT) calculations, (i) the intrinsic (100) surface states are not gap states but located …
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Electrical characterization of organic devices: case study: polythiophene-fullerene based solar cells
… of metallic electrode. The hypothesis of Fermi level pinning of the workfunction of the metallic electrode to the LUMO level of the acceptor could not be confirmed in the case of P3HT:PCBM based solar cells. The thermal annealing applied to P3HT:PCBM based solar cells, was found to be a …
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Controlled growth and doping of core-shell GaAs-based nanowires
… factors taking into account the effects of Fermi level pinning. The control demonstrated over all of these parameters is sufficient enough for core-shell nanowires to be considered candidates for high mobility electronics.
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Growth and characterisation of group-III nitride-based nanowires for devices
… The doping concentration and the position of the Fermi-level in InN depend very much on the crystalline quality. In general the luminescence of GaN and InN improves with increased Tsub. For GaN the defect-related peaks decrease and in InN the carrier concentration is reduced, which changes the …
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Spectroscopic characterisation of high dielectric constant materials on semiconducting surfaces
… to a high interface state density and associated Fermi level pinning which is avoided by utilizing a high-κ/Si interface instead of the high-κ/GaAs interface. The surface treatment prior to silicon deposition is shown here to be a critical step in reducing this effect. Samples with and without …
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Synthesis of large-area two-dimensional materials for vertical heterostructures
… and experiment, the implications of defects and Fermi level pinning on device performance were explored. In particular, this work demonstrates the potential of 2D vertical heterostructure devices and provides a path toward realizing high performance devices through device design and optimization …
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DEFECTS AND LIFETIME PREDICTION OF GERMANIUM MOSFETS
… has been proposed: there are a spread of energy levels of neutral hole traps below Ev andthey lift up after charging, and return below Ev after neutralization.The energy distribution of positive charges in the Al2O3/GeO2/Ge gate stack was studied by the Discharge-based Multi-pulse (DMP) …
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Phasenkohärenter Transport und Spin-Bahn-Wechselwirkung in III/V-Halbleiternanodrähten
… The underlying reason is that in InAs or InN the Fermi-level pinning in the conduction band results in a carrier accumulation at the surface. In fact, the tubular topology of the surface electron gas opens up the possibility to observe unconventional quantum transport phenomena. When the …
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Photonic studies of defects and amorphization in ion beam damaged GaAs surfaces
… depth) were dominated by the effect of Fermi level pinning at the electronic states of process-induced defects. Deep level transient spectroscopy (DLTS) indicated the presence of at least two distinct deep trap levels, at 0.32 eV and at 0.52 eV below the conduction band edge, as a …
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Physical investigations of novel materials and structures for Nano-MOSFETs
… contacts with abrupt junctions. However, due to Fermi-level pinning at the metal-semiconductor interface, the performance of SB-MOSFETs still falls behind that of conventional FETs. Nickel-silicidation induced dopant segregation is highly effective in improving carrier injection through SBs, …
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