A.E. Miller

Bio: A.E. Miller is an academic researcher from University of Notre Dame. The author has contributed to research in topics: Quantum dot & Nanolithography. The author has an hindex of 14, co-authored 32 publications receiving 1487 citations.

Self-ordered pore structure of anodized aluminum on silicon and pattern transfer

Abstract: A practical approach of transferring a hexagonal array of nanosized pores produced in porous alumina into silicon and other substrates is discussed. The alumina pores have dimensions of 25–250 nm pore diameters and 50–300 nm pore spacings depending on the anodization conditions used. The characteristics of the alumina pores and the alumina–silicon interface are studied for different substrate materials and anodizing conditions. The unique structure of the barrier layer allows for the alumina to be directly used as an etch mask for pattern transfer into the silicon substrate.

Electrochemically assembled quasi-periodic quantum dot arrays

Abstract: We describe two electrochemical self-assembly processes for producing highly ordered quasi-periodic arrays of quantum dots on a surface. The advantages of these techniques are: (i) they are `gentle' and do not cause radiation damage to nanostructures unlike beam lithography, (ii) they have high throughput and are amenable to mass production unlike direct-write lithography, (iii) structures can be delineated on non-planar substrates, and (iv) the techniques are potentially orders of magnitude cheaper to implement than conventional nanosynthesis. Samples produced by these techniques have been characterized by microscopy, optical and transport measurements, Auger and x-ray. These measurements reveal intriguing properties of the nanostructures. In this paper, we describe our initial results and show the promise of such techniques for low-cost and high-yield nanosynthesis.

Electrochemical synthesis of quasi-periodic quantum dot and nanostructure arrays

Abstract: A method of fabricating two-dimensional regimented and quasi periodic arrays of metallic and semiconductor nanostructures (quantum dots) with diameters of ˜100 Å(10 nm) includes the steps of polishing and anodizing a substrate to form a regimented quasi-periodic array of nanopits. The array forms a template for metallic or semiconductor material. The desired material is deposited in the nanopits by immersing the substrate in an appropriate solution and using the substrate as one cathode and inserting a second cathode in the solution.

Supercomputing with spin-polarized single electrons in a quantum coupled architecture

Abstract: We describe a novel quantum technology for possible ultra-fast, ultra-dense and ultra-low-power supercomputing. The technology utilizes single electrons as binary logic devices in which the spin of the electron encodes the bit information. Both two-dimensional cellular automata and random wired logic can be realized by laying out on a wafer specific geometric patterns of quantum dots each hosting a single electron. Various types of logic gates, combinational circuits for arithmetic logic units, and sequential circuits for memory have been designed. The technology has many advantages such as (1) the absence of physical interconnects between devices (inter-device interaction is provided by quantum mechanical spin-spin coupling between single electrons in adjacent quantum dots), (2) ultra-fast switching times of approximately 1 picosecond for individual devices, (3) extremely high bit density approaching 10 terabits cm-2, (4) non-volatile memory, (5) robustness and possible room-temperature operation with very high noise margin and reliability, (6) a very low power delay product ( approximately 10-20 J) for switching between logic levels, and (7) a very small power dissipation of a few tens of nanowatts per switching event. In spite of the above advantages, the technology also has some serious drawbacks in that the fan-out of individual logic devices may be small, wiring crossover is very problematic and the devices themselves have no inherent gain so that isolation between input and output is virtually non-existent. These are problems that plague all similar quantum technologies although they are seldom recognized as such. We will discuss these problems, and where possible, offer plausible solutions. In spite of these drawbacks, however, there are still enough attractive features of this technology to merit serious research. In this paper, we will describe how the spin-polarized single-electron logic devices work, along with the associated circuits and architecture. Finally, we will propose a new fabrication technique for realizing these chips which we believe is much more compatible with the demands of the technology than conventional nanofabrication methods.

Titanium oxide nanotube arrays prepared by anodic oxidation

Abstract: Titanium oxide nanotubes were fabricated by anodic oxidation of a pure titanium sheet in an aqueous solution containing 0.5 to 3.5 wt% hydrofluoric acid. These tubes are well aligned and organized into high-density uniform arrays. While the tops of the tubes are open, the bottoms of the tubes are closed, forming a barrier layer structure similar to that of porous alumina. The average tube diameter, ranging in size from 25 to 65 nm, was found to increase with increasing anodizing voltage, while the length of the tube was found independent of anodization time. A possible growth mechanism is presented.

Single-electron devices and their applications

Abstract: The goal of this paper is to review in brief the basic physics of single-election devices, as well as their-current and prospective applications. These devices based on the controllable transfer of single electrons between small conducting "islands", have already enabled several important scientific experiments. Several other applications of analog single-election devices in unique scientific instrumentation and metrology seem quite feasible. On the other hand, the prospect of silicon transistors being replaced by single-electron devices in integrated digital circuits faces tough challenges and remains uncertain. Nevertheless, even if this replacement does not happen, single electronics will continue to play an important role by shedding light on the fundamental size limitations of new electronic devices. Moreover, recent research in this field has generated some by-product ideas which may revolutionize random-access-memory and digital-data-storage technologies.

Powering MEMS portable devices—a review of non-regenerative and regenerative power supply systems with special emphasis on piezoelectric energy harvesting systems

Abstract: Power consumption is forecast by the International Technology Roadmap of Semiconductors (ITRS) to pose long-term technical challenges for the semiconductor industry. The purpose of this paper is threefold: (1) to provide an overview of strategies for powering MEMS via non-regenerative and regenerative power supplies; (2) to review the fundamentals of piezoelectric energy harvesting, along with recent advancements, and (3) to discuss future trends and applications for piezoelectric energy harvesting technology. The paper concludes with a discussion of research needs that are critical for the enhancement of piezoelectric energy harvesting devices.

Two-bit gates are universal for quantum computation

Abstract: A proof is given, which relies on the commutator algebra of the unitary Lie groups, that quantum gates operating on just two bits at a time are sufficient to construct a general quantum circuit. The best previous result had shown the universality of three-bit gates, by analogy to the universality of the Toffoli three-bit gate of classical reversible computing. Two-bit quantum gates may be implemented by magnetic resonance operations applied to a pair of electronic or nuclear spins. A ``gearbox quantum computer'' proposed here, based on the principles of atomic-force microscopy, would permit the operation of such two-bit gates in a physical system with very long phase-breaking (i.e., quantum-phase-coherence) times. Simpler versions of the gearbox computer could be used to do experiments on Einstein-Podolsky-Rosen states and related entangled quantum states.