Mircea Dragoman

Implementation of the spatial and the temporal cross-ambiguity function for waveguide fields and optical pulses

On the basis of space-time duality, we propose experimental setups to implement the cross-ambiguity function optically in space and time in one and two dimensions. In space the cross-ambiguity is shown to be related to the coupling efficiency between butt-joined optical waveguides. In time it is related to the spectrogram or the frequency-resolved optical gating techniques for the characterization of optical pulses.

Recovery of the refractive-index profile from the wigner distribution of an optical waveguide.

We propose a new method for the recovery of the refractive-index profile of a single-mode or multimode optical guided structure. We solve the inverse problem using the Wigner distribution and reduce it to the solution of a linear system of equations.

Analogies Between Ballistic Electrons and Electromagnetic Waves

One of the best known and most widely exploited analogies between classical physics and quantum mechanics is that between the time-independent Schrodinger equation and the Helmholtz equation, i.e., the time-independent form of Maxwell’s equations. Electrons in bulk semiconductors or heterostructures do not behave like waves, and thus cannot be described by the Schrodinger equation unless: (i) the interactions between electrons and the periodic crystal lattice, and between different electrons, do not appear explicitly in the electron equation of motion (ii) the collisions between different electrons as well as the interference effects between the wavefunctions of different electrons can be neglected.

Electronic Devices Based on Atomically Thin Materials

This chapter is dedicated to electronic devices based on 2D materials. The chapter starts with transistors, which are the backbone of integrated circuits, and continues with more complex devices and circuits, such as sensors, integrated circuits, and memories. This research area is in its infancy since only flakes of 2D materials are used. Thus, only few devices can be integrated, and the reproducibility and scalability issues are still not solved. The electronic devices based on 2D materials have a long path ahead before reaching the performances of Si-based integrated circuits, which actually contain up to five billions transistors/chip.

2D Carbon-Based Nanoelectronics

This chapter is dealing with the physics and applications of graphene in nanoelectronics, sensors and optoelectronics. Therefore, the physical properties of graphene presented in this chapter, as well as the specific phenomena encountered in this material, are directly linked to the electronic or optoelectronic devices.

Two-Dimensional Materials

In this chapter we present the recently discovered two-dimensional materials and their physical properties, which are useful for nanoelectronic devices. The synthesis methods play a central role in this chapter, since this is the key issue in the further development of this new emerging area of research. Details about characterization of these atomically thin materials are intrinsically linked to the growth methods.

Fundamentals on Bionanotechnologies

This is the introductory chapter of the book. The basic theoretical and experimental facts regarding the application of electronics at the nanoscale and for biological systems are developed here. Transport phenomena at the nanoscale, the principles of nanotechnologies, the physical properties of biological materials, and micro/nanofluidics are reviewed and explained in this chapter. The knowledge gained in this chapter will then be used in the entire book.

Biomolecular Architecture for Nanotechnology

This chapter reviews the design principles of biomolecular architecture with applications in nanotechnology and presents examples of zero-, one-, two-, and three-dimensional patterns of inorganic materials assembled on biological scaffolds. The use of nanoscale inorganic scaffolds for biomolecules is briefly discussed. Electronic nanoscale components separated by nanosized distances, which eventually lead to faster computation, require new technologies. One possible solution to the new generation of nanotechnologies involves the use of biological molecules, and in particular DNA, as scaffolds for electronic circuits. The advantages of DNA scaffolds are the self-assembly process and the specificity of A–T and G–C hydrogen-bonding interactions, as well as our present ability to synthesize and amplify any desired DNA sequence. In addition, the nanostructures constructed from DNA scaffolds are physicochemically stable, which means that they can be stored and processed under environmental conditions that do not need to be especially restrictive to avoid decomposition. The processing of DNA material can be performed with atomic precision by highly specific enzymes. Because of the relevance of DNA architecture to nanotechnology, many reviews exist on this subject (see, e.g., Seeman 1998; Feldkamp and Niemeyer 2006; Jaeger and Chworos 2006; Lin et al. 2009). We only focus here on specific examples of DNA-based fabrication of inorganic nanoparticle arrays or devices with applications in nanotechnology [see also (Li et al. 2009) for a recent review]. In most cases, nanotechnology-related scaffolding relies on the possibility of attaching chemical groups at certain positions, on which properly functionalized inorganic molecules bind in a subsequent process. DNA-based nanotechnology is a bottom-up self-assembly approach that follows a different strategy compared to inorganic self-assembly: nonequilibrium processes direct the assembly in biological structures, whereas equilibrium-regulated processes are commonly employed in artificial inorganic structures.

Sensing of Biomolecules

This chapter is dedicated to the label-free detection of various biomolecules using nanodevices such as field-effect transistors having channels with nanometric dimensions made from various nanomaterials like nanowires, nanotubes, or graphene; cantilevers, optical waveguides, nanopores, and other nanosized devices will be described for sensing of biomolecules.

Nano-Bio Integration

The aim of nanobiotechnology is the integration of nanodevices with biological molecules, such that both components maintain their functionalities. This chapter provides examples of such hybrid materials and devices.