Research groups around the world are looking to develop a qubit protected from decoherence for achieving quantum advantage in computations. This would have huge impact on the modern world. The applications are many from drug development to cryptography and many more  elds. Indium-Arsenide Nanowires with an epitaxially matched thin  lm of lead grown with Select-Area-Growth could prove to be a platform for building scalable qubits. The work in this thesis is to create a device capable of measuring the superconductivity of the samples InAs-Pb grown at the Center for Quantum Devices, Niels Bohr Institute. The InAs semiconducting nanowires serves as one dimensional system that could host Majorana Zero Modes if coupled to a superconductor such as Pb. The MZMs emerges at the edges of the nanowires. The device created is a 4-probe device that should be used to measure the induced topological superconductivity inside the device. The project was able to such a device using electron beam lithography techniques and development of the fabrication process of InAs-Pb SAG NW Devices was furthered.

Laser lithography was used to create novel patterns in thin diblock copolymer films. These patterns were characterized and an examination of their formation and growth was conducted. The patterns occurred only in diblock films, due to the interaction between thermal gradient induced Marangoni flow and the self assembly of the molecules. Growth of the patterns was found to be strongly dependent on absorbed power. The impact of film thickness on pattern growth was mainly due to the corresponding changes in sample reflectance, however a periodic patterning was observed suggesting that growth is also dependent on the amount of 'excess' material (over that required to form complete lamella) available. It was also shown that the pattern growth can occur independently of laser lithography and the Marangoni effect, though laser lithography was required to direct this growth. / Thesis / Master of Applied Science (MASc)

Laser lithography has been implemented in many ways to pattern polymeric materials. By using a tightly focused laser beam we can induce sharp thermal gradients, exceeding 1,500,000 °C/cm, onto the surface of a thin polymer film. The temperature dependence of the surface tension in such a thermal field gives rise to a flow of material away from the center of the beam focus driven by the Marangoni or thermocapillary effect. The evolution of a film irradiated by a focused laser can be, in a general sense, predicted by a presented hydrodynamic model, which is based on simple fluid mechanics. However, the details of the individual evolution profiles show a more complicated behaviour. It has been shown that this complex behaviour can be explained by considering the optical interference effects of the thin polymer coating. An optical feedback control routine has been developed to compensate for the interference effect by monitoring and maintaining a constant absorbed laser power. This ensures that the temperature gradient that drives the lithography process is consistent during operation. Additional studies involving high laser power effects, different material systems and other thin film phenomena have revealed an interesting assortment of novel behaviours. The extension of these behaviours to the lithography process lead towards the development of applications in microfabriation and microfluidic devices. / Thesis / Master of Applied Science (MASc)

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This study describes the covalent and the electrostatic attachment of molecules, nano-particles, and proteins to patterned self-assembled monolayers. A scanning probe nanografting technique was employed to produce patterns of various sizes, down to 10 nm. Thus, we are able to demonstrate a degree of surface patterning which is an order of magnitude smaller than that used in the semiconductor industry. One efficient strategy for creating chemically specific nanostructures is to use the extraordinary catalytic properties of enzymes. However, as the dimension of a catalyst patch is reduced down to nanometer scale, it is difficult to detect the very low concentration of product. This study resolves the problem by developing a new strategy: the surface trapping of a product generated by a nanometer-scale patch of surface-bound enzyme. An array of proteins finds use when the array contains a number of different proteins. Toward this end, a new and convenient method for immobilizing enzymes is developed, which will allow the preparation of thin films containing several different catalytically-active enzymes on the nanoscale. The disadvantage of scanning probe nanografting technique is that the AFM tip loses resolution through wear during the patterning procedure. This study examines the possibility of developing a new AFM lithographic method to avoid wear: the use of enzymes covalently attached to a tip as a site-specific catalyst. / Ph. D.

In the present investigation, a comprehensive photonic characterization and analysis of low energy Ar⁺ ion beam processed GaAs surfaces is presented. The purpose of this investigation was to evaluate the damage and amorphization introduced at the surface and sub-surface regions by ion bombardment. Ar⁺ ion beam etching was selected in order to rule out the possibility of producing any additional effects at the interface due to chemical reactions in the case of reactive ion etching. After a brief review of the concepts and underlying physics, several photonic structures are introduced. The basic theory governing the photovoltaic devices and photoconductive samples is discussed. The preparation and characterization techniques of ion beam processed GaAs samples are described. An automated photovoltaic materials and devices (PVMD) system was developed. Asyst, a Forth based scientific software was selected to write the source codes for data acquisition and reduction. The inherent fast execution times of the software allows data acquisition in real time, ensuring the quasi-steady state condition. The electrical and optical evaluation procedures developed and employed for the present investigation are discussed. One of the striking features of the ion beam bombardment on semi-insulating (SI) GaAs samples was the observation of persistent photoconductivity. A phenomenological model for optically generated ion beam induced metastable defect state formation was proposed to explain the persistent photoconductivity. Presence of two or more exponential curves in the relaxation mode indicates the distributed nature of the traps within the band gap. A conjectural flat-band energy diagram was introduced to elucidate the proposed model. The observed dark and photoconductivity response model was based on the distributed lumped electrical components analysis. Fundamental transport equations were employed in the analysis of the lumped electrical components model. Metal-Insulator-Semiconductor (MIS) type Schottky barrier diodes and photodiodes were fabricated employing both thermal and anodic oxides. Diode parameters were evaluated as a function of ion-beam energy. An increase in reverse saturation current density accompanied by an increase in the ideality factor was observed, indicating the presence of trap-assisted tunneling and a region of high recombination. The effective barrier height was generally lowered; however, no monotonic correlation with the ion energy was observed. It is proposed that the mechanisms described in previous studies (e.g. tunneling, stoichiometry effects, ion penetration 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 consequence of ion beam etching. The EL2 peak was evident in the virgin sample and vanished in the ion beam etched samples and such observation is in agreement with our proposed model. The photovoltaic response was characterized using illuminated current-voltage (I-V) and spectral response measurements. The ratio of external quantum efficiencies of IBE devices to unetched device indicates the regions and relative extent of the damage. Since the damage has a impact on the band-bending due to excess carrier generation, the sub-bandgap photon absorption response reveals the degree of disorder. XPS results indicated an increased surface sensitivity and change in Ga/As ratio as a function of ion beam energy. The modelling of ion-beam-processed samples was considered and several computer programs which simulate their operation are described. The depth of amorphization was calculated using the Lindhard-Scharff-SchiΦtt (LSS) theory and the standard projected range and straggle parameters, and experimental parameters. A large difference was observed in the values calculated using LSS theory and experimentally measured values, using optical probes. The difference was explained in light of the Collision-Cascade model. / Ph. D.

Over the past decade there has been an explosion in the demand for wireless mobile personal communications systems (PCS), a trend that shows no signs of slowing down in the foreseeable future. This demand has created a greater need for low-cost, low-power, compact system solutions. As a result, "single-chip" implementations of wireless functions have received a significant amount of attention. A significant roadblock to complete integration of these functions is the requirement for high-Q resonators in RF filter and tank circuits. Current on-chip techniques being used to realize monolithic RF resonators based on planar inductors, capacitors and active circuits are accompanied by problems such as high loss, large chip area and high power consumption. An alternative to these on-chip solutions is the use of monolithically integrated electromechanical devices. This thesis describes the modeling, fabrication and characterization of nanoelectromechanical (NEM) single crystal silicon resonators. The potential advantages associated with these devices are high-Q, small die area and low power consumption. The development of such devices compatible with modern integrated circuit fabrication techniques offers the possibility for integration of high performance RF filters and resonators onto a single RFIC chip. The advantageous characteristics of these resonators could lead to mobile PCS devices with lower cost and increased battery life. The NEM resonator designs investigated in this work are fabricated using an electron-beam lithography based surface machining process in silicon-on-insulator technology. Various design, fabrication and testing issues are discussed. The feasibility of lateral capacitive actuation and detection in such structures is examined. / Master of Science