Semiconductor Nano Research Articles

Electrical Contacts to Vertically Oriented Silicon Nano and Microdevices for Applications in Flexible Systems

ABSTRACTFlexible devices utilizing crystalline semiconductor nano or microstructures materials are attractive for many applications. However, these materials are fabricated or grown in unusable forms for flexible systems due to their rigid crystalline mother substrates. We demonstrate a transfer printing technique for transferring vertical arrays of one-dimensional (1D) materials from mother substrates to flexible substrates with subsequent device fabrication steps to create flexible devices from these arrays. The transfer printing technique is based on vertical embossing of arrays of 1D materials into thermoplastic (Poly (methyl methacrylate) (PMMA)) transfer layers, while the device fabrication steps rely on encapsulation with insulating polymers and contact deposition. We investigated the use of flexible insulating layers like polydimethylsiloxane (PDMS) and polyurethane (PU) which are shown to be effective for encapsulation and contact isolation. Representative flexible resistive devices were created from these transferred arrays and insulating layers which showed a reversible tactile characteristic. Electronic characterization and flexibility testing was carried out to show the potential of these methods for enabling large-scale integrations of nano and microstructures into vertical and flexible packages.

Implementation of Electrochemical Methods for Metrology and Analysis of Nano Electronic Structures of Deep Trench DRAM

In the course of feasibility study the necessity of implementing electrochemical methods as an inline metrology technique to characterize semiconductor nano structures for a Deep Trench Dynamic Random Access Memory (DT-DRAM) (e.g. ultra shallow junctions USJ) was discussed. Hereby, the state of the art semiconductor technology on the advantages and disadvantages of the most recently used analytical techniques for characterization of nano electronic devices are mentioned. Various electrochemical methods, their measure relationship and correlations to physical quantities are explained. The most important issue of this paper is to prove the novel usefulness of the electrochemical micro cell in the semiconductor industry.

Honorary Chairman Dieter Bimberg

AbstractDieter H. Bimberg was born in Schrozberg/Germany on 10 July, 1942. He received the Diploma in physics and the Ph.D. degree from Goethe University Frankfurt in 1968 and 1971, respectively. From 1972 to 1979 he held a Principal Scientist position at the Max Planck Institute for Solid State Research in Grenoble/France and Stuttgart/Germany. In 1979 he was appointed as Professor of Electrical Engineering, Technical University of Aachen. Since 1981 he has held the Chair of Applied Solid State Physics at Technical University (TU) Berlin. Since 1990 he has been Executive Director of the Solid State Physics Institute at TU Berlin. From 1994 to 2006 he was Chairman of the DFG Collaborative Research Center (CRC) “Growth Related Properties of Nanostructures”. In 2007 he founded the DFG‐CRC on “Semiconductor Nano Photonics” which will operate until 2018. He has chaired the bmb+f “National Center of Competence on Nano‐Opto‐electronics” since 1998 and the joint board of the Federal Government Nanotechnology Centers of Competence since 2006. He holds guest professorships at Technion, Haifa (twice), University of California, Santa Barbara, and Hewlett‐Packard, Palo Alto/CA. His honors include the Japanese Prize of Applied Physics in 1988 and the Russian State Prize in Science and Technology in 2002. He is honorary Member of the A. F. Ioffe Physico‐Technical Institute of the Russian Academy of Sciences. Since 2004 he has been full member of the German National Academy of Sciences “Leopoldina” and a Fellow of the American Physical Society. In 2009 he was elected Fellow of the Institute of Electrical and Electronics Engineers (IEEE). Dieter Bimberg has authored more than 1000 papers, 20 patents, and 6 books. The number of his citations is over 24000 and his Hirsch index is 68. His research interests include physics and technology of nano¬structures and nanostructured devices like quantum‐dot lasers and amplifiers, wide‐gap semiconductor heterostructures, GaN‐based lasers, ultrahigh‐speed photonic devices, single electron devices, and quantum cryptography (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

ChemInform Abstract: Semiconductor Nanoparticles with Spatial Separation of Charge Carriers: Synthesis and Optical Properties

AbstractReview: 165 refs.

Emission of Terahertz Radiation from Two-Dimensional Electron Systems in Semiconductor Nano- and Hetero-Structures

This paper reviews recent advances in emission of terahertz radiation from two-dimensional (2D) electron systems in semiconductor nano-heterostructures. 2D plasmon resonance is first presented to demonstrate intense broadband terahertz emission from InGaP/InGaAs/GaAs and InAlAs/InGaAs/InP material systems. The device structure is based on a high-electron mobility transistor and incorporates the author’s original interdigitated dual-grating gates. Second topic focuses on graphene, a monolayer carbon-atomic honeycomb lattice crystal, exhibiting unique carrier transport and optical properties owing to massless and gapless energy spectrum. Coherent stimulated terahertz emission from femtosecond infrared-laser pumped epitaxial graphene is experimentally observed, reflecting the occurrence of negative dynamic conductivity and population inversion.

Temperature stable positive magnetic susceptibility of semiconductor wobbled nano rings

We theoretically investigate the magnetic response of ensembles of semiconductor nano rings. Using our mapping method we simulated geometrical and material dispersion of the magnetic susceptibility of ensembles of the rings. Unlike the susceptibility of an individual ring the averaged susceptibility shows small temperature effect.

Magneto-optics of layers of double quantum dot molecules

We present a general treatment of the magneto-optical response from systems of semiconductor nano objects of arbitrary shapes. Our theoretical hybrid method allows us to simulate the coherent manipulation of the quantum states of electrons and holes in nano objects and monitor that by means of analysis of the collective magneto-optical response from the system. As an example of the method implementation we consider the coherent manipulation of the electronic states of a asymmetrical double InAs quantum dot molecule embedded in GaAs matrix and the collective magneto-optical properties of a layer of the molecules. Our simulation results show that changes in the quantum-mechanical configuration of the quantum dot molecules can be observable by monitoring changes in the ellipsometric data obtained for layers made from these nano objects. The ellipsometric data clearly represent the quantum mechanics of the molecules.

Acoustic phonon engineering of thermal properties of silicon-based nanostructures

We have theoretically studied the influence of the nanostructure cladding materials on the phonon thermal conduction in the Si-based planar heterostructures and rectangular hetero-nanowires. The phonon energy spectra were obtained in the framework of the face-centered cell-dynamic lattice model. Using this model we have shown that the nanostructure claddings with the low sound velocity decrease the phonon group velocities and thermal conductivity in the nanostructures, while the claddings with high sound velocities have the opposite effect. The described modification of the thermal conductivity of the semiconductor nano- and heterostructures may have important consequences for electronic industry in a view of continuing miniaturization.

Reduction of Interpore Distance of Anodized Aluminum Oxide Nano Pattern by Mixed H3PO4:H2SO4 Electrolyte

A self-formed and ordered anodized aluminum oxide (AAO) nano pattern has generated considerable interest in both scientific research and commercial application. However, the interpore distance obtainable by AAO is limited by 40-500 nm depending on electrolyte and anodizing voltage. It's believed that below-30 nm AAO pattern is a key technology in the fabrication semiconductor nano structures with enhanced quantum confinement effect, so we worked on the reduction of interpore distance of AAO with a novel electrolyte. AAO nano patterns were fabricated with mixed H2SO4 and H3PO4 as an electrolyte for various voltages and temperatures. The interpore distance and pore diameter of AAO were decreased with reduced anodizing voltage. As a result, an AAO nano pattern with the interpore distance of 27 nm and the pore diameter of 7 nm was obtained. This is the smallest pattern, as long as we know, reported till now with AAO technique. The fabricated AAO pattern could be utilized for uniform and high density quantum dots with increased quantum effect.

Cathodoluminescence of Elongated Semiconductor Nano- and Microstructures

Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2006

Confinement-Induced versus Correlation-Induced Electron Localization and Wave Function Entanglement in Semiconductor Nano Dumbbells

Single-particle plus many-particle calculations of the electronic states of semiconductor nano dumbbells show how geometrical features (e.g., the width of the dumbbell wire) determine, through quantum confinement and electron−electron correlation effects, the spatial localization and the degree of entanglement of the electronic wave functions. Remarkably, we find that correlation effects can alter carrier localization and that the degree of wave function entanglement can be tuned by changing the diameter of the dumbbell wire. We further show how the exciton binding energy depends on the nano dumbbell geometry.

Materials Chemistry of 1,2,3-Selenadiazoles

The organic chemistry of 1,2,3-selenadiazoles has been explored to a greater extent due to the fact that the chemistry of 1,2,3-selenadiazoles mostly is driven by its facile decomposition via elimination of a nitrogen molecule and formation of selenaketocarben and/or its dimerization to 1,4-diselenin. The reactions of 1,2,3-selenadiazoles directly with various transition metal compounds have resulted in unique organo-selenium transition metal complexes. However, the materials chemistry of 1,2,3-selenadiazoles has not appeared in literature prior to the first publication on the subject from our laboratory in 2003. To, the best of our knowledge, no research group is engaged in such an activity. We, have exclusively explored the potential of 1,2,3-selenadiazoles for their effective utilization in synthesis of semiconductor nano particles or nano powder and in this lecture, the results and methodology for the same would be discussed.

Development of single-ion hit techniques and their applications at TIARA of JAERI Takasaki

At TIARA facility in JAERI Takasaki, the single-ion hit technique combined with heavy ion microbeam has evolved in conjunction with developments in applied research such as the study of single-ion irradiation effects in semiconductors or biological cells. This technique is the most effective tool for the investigation of individual phenomena induced by single-ion injections to local areas of those samples, which have micron-scale structures. Adding a feature of position detection for the study of single event effects in semiconductor nano- or quantum devices is regarded as the next stage in the development of the single-ion hit technique.

NEWS OF THE WEEK

THE SEMICONDUCTOR NANO particles known as quantum dots have moved closer to biological applications, according to two recent reports. In one paper, scientists at Cornell University, collaborating with Quantum Dot Corp. in Hayward, Calif., use quantum dots as a label for multiphoton imaging in live animals. In the other report, Japanese researchers use chaperone proteins to encapsulate and protect quantum dots, preventing them from aggregating and losing their size-dependent properties. Watt W.Webb, professor of applied physics at Cornell University, and his coworkers injected amphiphiliccoated quantum dots made of CdSe-ZnS intravenously into mice {Science, 300,1434 (2003)}. Using multiphoton microscopy, they obtained images of bloodvessels through skin and fat—tissues that are challenging for imaging because they scatter and absorb radiation. They could easily measure blood flow and detect heart rate direcdy through the skin. The combination of quantum dots and multiphoton microscopy(in which multiple low...

Laser Science of a Single Microparticle. Optical Properties of Single Nano Particles of Semiconductors and Their Potentialities for Application to Devices.

Optical properties of semiconductor nano particles are reviewed, especially on I-VII and II-VI compounds from the view points of fundamental photophysics brought about by quantum size effects on three-dimensionally confined excitonic systems and also of new prospective functional photonic materials. Various kinds of size-dependent excitonic properties in nano particles of individual sizes or individual nano particles are found by means of size-selective excitation and microspectroscopic photo-luminescence measurements. Near-field optical responses in assembled nano particles are also discussed. Their potentialities for application to nano opto-electronic devices are briefly mentioned.