BDD Minimization for Approximate Computing

We present Approximate BDD Minimization (ABM) as a problem that has application in approximate computing. Given a BDD representation of a multi-output Boolean function, ABM asks whether there exists another function that has a smaller BDD representation but meets a threshold w.r.t. an error metric. We present operators to derive approximated functions and present algorithms to exactly compute the error metrics directly on the BDD representation. An experimental evaluation demonstrates the applicability of the proposed approaches

Design of Reconfigurable On-Chip Optical Architectures based on Phase Change Material

Integrated optics is a promising technology to take the advantage of light propagation for high throughput chip-scale computing architectures and interconnects. Optical devices call for reconfigurable architectures to maximize resource utilization. Typical reconfigurable optical computing architectures involve micro-ring resonators for electro-optic modulation. However, such devices require voltage and thermal tuning to compensate for fabrication process variability and thermal sensitivity. To tackle this challenge we propose to use non-volatile Phase Change Material (PCM) to configure optical path. The non-volatility of PCM elements allows maintaining the optical path without consuming energy and the high contrast between two state of crystalline (cr) and amorphous (am) allows to route signal only through the required resonators, thus saving the calibration energy of bypassed resonators. We evaluate the efficiency of PCM based design on Reconfigurable Directed Logic (RDL) and nanophotonic interconnect. We develop a model allowing to estimate optical and electrical energy consumption. In the context of nanophotonic interconnect we evaluate the efficiency of the proposed PCM-based interconnects using system level simulations carried out with SNIPER manycore simulator. Results show that the proposed implementation allows reducing the static power by 53% on average for RDL and communication power saving up to 52% is achieved for nanophotonic interconnect

Electrical and electrochemical characterisation of single crystal diamond

The overall aim of this thesis is to examine the electrical and electrochemical properties of single crystal intrinsic and boron doped diamond grown by chemical vapour deposition. Techniques such as AFM, C-AFM, FE-SEM, PL imaging, in air and in solution Hall and resistivity measurements, FET, cyclic voltammetry and SECM have been employed. The results from studying single crystal intrinsic H-terminated diamond with different surface preparations are reported. In air and in solution measurements suggest a similar behaviour for polished surfaces. Different mechanisms (for in air or in solution experiments) have to be applied in order to interpret the electrical transport data correctly. Electrochemistry of H-terminated single crystal diamond with well defined redox couples has been proven, but the electron transfer rates are relatively slow. Initial SECM experiments indicate that the surface is homogeneously active, but can be easily damaged. Single crystal boron doped diamonds with moderate (< 1020 cm-3 boron) doping levels have been examined. PL imaging and C-AFM highlighted regions with different doping level and different conductivity even though the material is single crystal. In air electrical measurements demonstrated that the bulk mobility and carrier concentration are independent of the surface termination (O- or H-). No redox activity (or very little) was observed when the samples were O-terminated; quasi-reversible behaviour and sluggish electron transfer kinetics was observed for H-terminated surfaces. The properties of a as-grown single crystal boron doped diamond with high (> 1020 cm-3 boron) doping levels have also been investigated. Electrical studies confirmed that the diamond behaved like a metallic conductor. Large background currents were observed when CVs were used to study the O-terminated sample in FcTMA+, but the origin of this signal are not clear. For both Ru(NH3)6 3+ and FcTMA+ the metallic boron doped single crystal diamond electrode showed quasi-reversible behaviour. The peak to peak separation is smaller for the H-termination than for the O-termination. Preliminary SECM studies showed that the electrode’s surface was homogeneously active

Cutting Edge Nanotechnology

The main purpose of this book is to describe important issues in various types of devices ranging from conventional transistors (opening chapters of the book) to molecular electronic devices whose fabrication and operation is discussed in the last few chapters of the book. As such, this book can serve as a guide for identifications of important areas of research in micro, nano and molecular electronics. We deeply acknowledge valuable contributions that each of the authors made in writing these excellent chapters

Electrogenerated chemiluminescence : from mechanistic insights to bioanalytical applications

Electrogenerated chemiluminescence (ECL) is a powerful analytical technique exploited for clinical, industrial and research applications. The high sensitivity and good selectivity, makes ECL a tool-of-choice analytical method for a broad range of assays, most importantly for a large number of commercialized bead-based immunoassays. In the present thesis, we aimed to study the ECL phenomenon and its application in development of new analytical methods.In the first part of this work, we used an imaging technique to investigate the ECL mechanisms operating in bead-based assays. Spatial reactivity mapping at the level of a single functionalised bead provides a new strategy to test the co-reactant efficiency and shows associated optical focusing effects.In the second part, the design of a novel anti-transglutaminase ECL immunoassay for celiac disease diagnostic is shown using nanoelectrode ensembles as bioelectroanalytical platforms. We also studied the characteristics of ECL generated by arrays of boron-doped-diamond nanoelectrodes (BDD NEAs) as a promising materials for bioapplications. The ECL efficiency of two co-reactants at BDD NEAs was investigated.Finally, bipolar electrochemistry is a ‘‘wireless’’ process that was exploited for the controlled motion of conductive objects exposed to an electric field in the absence of direct ohmic contact. In the third part of the thesis, we report ECL coupled to bipolar electrochemistry for tracking the autonomous trajectories of swimmers by light emission. We further expanded this concept for dynamic enzymatic sensing of glucose concentration gradient using ECL light emission as an analytical readout.La chimiluminescence électrogénérée (ECL) est une technique analytique puissante exploitée pour la détection autant au niveau industriel que dans le domaine de la recherche scientifique ou du diagnostic clinique. La sensibilité élevée et la bonne sélectivité de cette technique font de l'ECL une méthode analytique de choix pour un large éventail d'applications, dont la plus importante est son utilisation commerciale dans un grand nombre de tests immunologiques à base de billes fonctionnalisées. Dans cette thèse, nous avons cherché à étudier le phénomène ECL et son application pour le développement de nouvelles techniques analytiques.Dans la première partie de ce travail, nous utilisons les techniques d'imagerie pour étudier les mécanismes ECL se produisant sur les billes utilisées pour les tests immunologiques. La cartographie de la réactivité au niveau d'une seule microparticule fonctionnalisée avec un complexe de ruthénium fournit une nouvelle stratégie visant à tester l'efficacité du co-réactif et montre des effets optiques associés de focalisation.Dans la deuxième partie, la conception d'un test immunologique pour la détection de l'anti-transglutaminase pour le diagnostic de la maladie coeliaque est présentée en utilisant des ensembles de nanoélectrodes comme plates-formes bioélectroanalytiques. Nous avons également étudié les caractéristiques de l'ECL générée par des réseaux de nanoélectrodes dopées au bore-diamant en tant que matériaux prometteurs pour des applications biologiques ainsi que l'efficacité ECL de deux co-réactifs sur ces réseaux.L'électrochimie bipolaire est un processus sans contact que nous avons exploité pour contrôler le mouvement d'objets conducteurs exposés à un champ électrique en l'absence de contact ohmique direct. Dans la troisième partie de ma thèse, nous présentons l'ECL couplée à l'électrochimie bipolaire pour le suivi d’objets autonomes luminescents. Nous avons élargi ce concept à la détection enzymatique dynamique de glucose en utilisant l'émission de lumière ECL comme signal analytique

Electrical and electrochemical characterisation of single crystal diamond

The overall aim of this thesis is to examine the electrical and electrochemical properties of single crystal intrinsic and boron doped diamond grown by chemical vapour deposition. Techniques such as AFM, C-AFM, FE-SEM, PL imaging, in air and in solution Hall and resistivity measurements, FET, cyclic voltammetry and SECM have been employed. The results from studying single crystal intrinsic H-terminated diamond with different surface preparations are reported. In air and in solution measurements suggest a similar behaviour for polished surfaces. Different mechanisms (for in air or in solution experiments) have to be applied in order to interpret the electrical transport data correctly. Electrochemistry of H-terminated single crystal diamond with well defined redox couples has been proven, but the electron transfer rates are relatively slow. Initial SECM experiments indicate that the surface is homogeneously active, but can be easily damaged. Single crystal boron doped diamonds with moderate ( 1020 cm-3 boron) doping levels have also been investigated. Electrical studies confirmed that the diamond behaved like a metallic conductor. Large background currents were observed when CVs were used to study the O-terminated sample in FcTMA+, but the origin of this signal are not clear. For both Ru(NH3)6 3+ and FcTMA+ the metallic boron doped single crystal diamond electrode showed quasi-reversible behaviour. The peak to peak separation is smaller for the H-termination than for the O-termination. Preliminary SECM studies showed that the electrode’s surface was homogeneously active.EThOS - Electronic Theses Online ServiceGBUnited Kingdo