We present a comprehensive, up-to-date compilation of band parameters for the technologically important III–V zinc blende and wurtzite compound semiconductors: GaAs, GaSb, GaP, GaN, AlAs, AlSb, AlP, AlN, InAs, InSb, InP, and InN, along with their ternary and quaternary alloys. Based on a review of the existing literature, complete and consistent parameter sets are given for all materials. Emphasizing the quantities required for band structure calculations, we tabulate the direct and indirect energy gaps, spin-orbit, and crystal-field splittings, alloy bowing parameters, effective masses for electrons, heavy, light, and split-off holes, Luttinger parameters, interband momentum matrix elements, and deformation potentials, including temperature and alloy-composition dependences where available. Heterostructure band offsets are also given, on an absolute scale that allows any material to be aligned relative to any other.

Band parameters for III–V compound semiconductors and their alloys

Boron-doped silicon nanowires (SiNWs) were used to create highly sensitive, real-time electrically based sensors for biological and chemical species. Amine- and oxide-functionalized SiNWs exhibit pH-dependent conductance that was linear over a large dynamic range and could be understood in terms of the change in surface charge during protonation and deprotonation. Biotin-modified SiNWs were used to detect streptavidin down to at least a picomolar concentration range. In addition, antigen-functionalized SiNWs show reversible antibody binding and concentration-dependent detection in real time. Lastly, detection of the reversible binding of the metabolic indicator Ca2+ was demonstrated. The small size and capability of these semiconductor nanowires for sensitive, label-free, real-time detection of a wide range of chemical and biological species could be exploited in array-based screening and in vivo diagnostics.

/pdf/nanowire-nanosensors-for-highly-sensitive-and-selective-4f3aqhtkwe.pdf

Nanowire Nanosensors for Highly Sensitive and Selective Detection of Biological and Chemical Species

We present a comprehensive and up-to-date compilation of band parameters for all of the nitrogen-containing III–V semiconductors that have been investigated to date. The two main classes are: (1) “conventional” nitrides (wurtzite and zinc-blende GaN, InN, and AlN, along with their alloys) and (2) “dilute” nitrides (zinc-blende ternaries and quaternaries in which a relatively small fraction of N is added to a host III–V material, e.g., GaAsN and GaInAsN). As in our more general review of III–V semiconductor band parameters [I. Vurgaftman et al., J. Appl. Phys. 89, 5815 (2001)], complete and consistent parameter sets are recommended on the basis of a thorough and critical review of the existing literature. We tabulate the direct and indirect energy gaps, spin-orbit and crystal-field splittings, alloy bowing parameters, electron and hole effective masses, deformation potentials, elastic constants, piezoelectric and spontaneous polarization coefficients, as well as heterostructure band offsets. Temperature an...

Band parameters for nitrogen-containing semiconductors

Atomic layer deposition(ALD), a chemical vapor deposition technique based on sequential self-terminating gas–solid reactions, has for about four decades been applied for manufacturing conformal inorganic material layers with thickness down to the nanometer range. Despite the numerous successful applications of material growth by ALD, many physicochemical processes that control ALD growth are not yet sufficiently understood. To increase understanding of ALD processes, overviews are needed not only of the existing ALD processes and their applications, but also of the knowledge of the surface chemistry of specific ALD processes. This work aims to start the overviews on specific ALD processes by reviewing the experimental information available on the surface chemistry of the trimethylaluminum/water process. This process is generally known as a rather ideal ALD process, and plenty of information is available on its surface chemistry. This in-depth summary of the surface chemistry of one representative ALD process aims also to provide a view on the current status of understanding the surface chemistry of ALD, in general. The review starts by describing the basic characteristics of ALD, discussing the history of ALD—including the question who made the first ALD experiments—and giving an overview of the two-reactant ALD processes investigated to date. Second, the basic concepts related to the surface chemistry of ALD are described from a generic viewpoint applicable to all ALD processes based on compound reactants. This description includes physicochemical requirements for self-terminating reactions,reaction kinetics, typical chemisorption mechanisms, factors causing saturation, reasons for growth of less than a monolayer per cycle, effect of the temperature and number of cycles on the growth per cycle (GPC), and the growth mode. A comparison is made of three models available for estimating the sterically allowed value of GPC in ALD. Third, the experimental information on the surface chemistry in the trimethylaluminum/water ALD process are reviewed using the concepts developed in the second part of this review. The results are reviewed critically, with an aim to combine the information obtained in different types of investigations, such as growth experiments on flat substrates and reaction chemistry investigation on high-surface-area materials. Although the surface chemistry of the trimethylaluminum/water ALD process is rather well understood, systematic investigations of the reaction kinetics and the growth mode on different substrates are still missing. The last part of the review is devoted to discussing issues which may hamper surface chemistry investigations of ALD, such as problematic historical assumptions, nonstandard terminology, and the effect of experimental conditions on the surface chemistry of ALD. I hope that this review can help the newcomer get acquainted with the exciting and challenging field of surface chemistry of ALD and can serve as a useful guide for the specialist towards the fifth decade of ALD research.

Surface chemistry of atomic layer deposition: A case study for the trimethylaluminum/water process

and Fuels Changzhi Li,† Xiaochen Zhao,† Aiqin Wang,† George W. Huber,†,‡ and Tao Zhang*,† †State Key Laborotary of Catalysis, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China ‡Department of Chemical and Biological Engineering, University of WisconsinMadison, Madison, Wisconsin 53706, United States

Catalytic Transformation of Lignin for the Production of Chemicals and Fuels

We have studied (AlxGa1−x)0.5In0.5P doped with tellurium using deep level transient spectroscopy and associated electrical measurements. Several defect states are observed in the upper half of the band gap, that are believed to be intrinsic to the alloy system as well as related to the tellurium donors. Defects observed at measurement temperatures above 390 K exhibit a hysteretic behavior. The observed spectra depend on the biasing conditions applied to the Schottky diode during cooling. The hysteretic behavior suggests the existence of different defect configurations, which can be accessed under conditions of high temperatures and electrical stress, but remain stable below 300 K.

High-temperature hysteretic electronic effects of (AI x Ga 1-x ) 0.5 In 0.5 P(x > 0.65)

We have investigated the use of Metamorphic Buffer Layer (MBL) structures for the realization mid-infrared semiconductor lasers employing either interband or intersubband transitions. The resulting surface morphology of the MBL is generally cross-hatched along the orthogonal &#60;110> directions. This surface morphology may negatively impact device structures grown on top of the MBL. We have employed two different techniques to improve the surface morphology of MBLs, while maintaining an epiappropriate surface chemical composition and structure: (1) Introduction of Sb as a surfactant to create novel step-graded MBLs; and (2) Chemical-Mechanical-Polishing (CMP) of the MBL followed by MOCVD regrowth of layers atop the MBL.

http://ieeexplore.ieee.org/iel7/6469377/6472327/06472379.pdf

Metamorphic buffer layers for mid-infrared emitting semiconductor lasers

Verfahren zum Tempern eines ionenimplantierten Galliumarsenidsubstrates

Experiments and molecular dynamics (MD) simulations show that crystallization of amorphous Al2O3 via solid phase epitaxy (SPE) on a (0001), c-plane, α-Al2O3 substrate forms a metastable γ-Al2O3 polymorph before transforming eventually to α-Al2O3. MD simulations over a wide range of crystallization temperatures above the glass transition point Tg show that the growth velocity of epitaxial γ-Al2O3 follows the Wilson–Frenkel relation. The barriers associated with interfacial reorganization processes are minimal, indicating that mass transport to the amorphous–crystalline interface is the rate-limiting step over the entire temperature range for γ-Al2O3 SPE. The mechanisms of transport depend on the temperature and have a significant effect in determining the crystallization velocity. Above Tg, mass transport is controlled by bulk diffusion. Below Tg, the crystallization velocity is faster than predicted from the Wilson–Frenkel relation in both the MD and experimental results. X-ray characterization shows that the growth of epitaxial γ-Al2O3 follows an Arrhenius dependence on crystallization temperature from 700 to 800 °C with an apparent activation energy of 3.1 eV. Despite the fact that MD shows essentially no bulk diffusion at temperatures below Tg, SPE growth is nonetheless observed. Our simulations show that this persistent growth is the result of kinetic heterogeneity between bulk and interface, with epitaxial growth governed by enhanced diffusion near the amorphous–crystalline interface. The rate of interfacial diffusion is computed using a hopping rate based on the first passage time of atoms moving to neighboring crystallization sites. The combination of conventional diffusion and interfacial hopping modes of mass transport within the Wilson–Frenkel model provides an accurate estimate of the SPE growth velocity of γ-Al2O3 both above and below Tg. 

Kinetics and Mechanism of γ-Al2O3 Solid Phase Epitaxy on c-Plane α-Al2O3

We demonstrate continuously phase matched THz difference frequency generation (DFG) in a LiNbO3 nested waveguide structure with a power-normalized conversion efficiency of 1.3 times 10-7 W-1, 23 times more efficient than the best previously reported results.

Thomas F. Kuech

Papers

High-temperature hysteretic electronic effects of (AI x Ga 1-x ) 0.5 In 0.5 P(x > 0.65)

Metamorphic buffer layers for mid-infrared emitting semiconductor lasers

Verfahren zum Tempern eines ionenimplantierten Galliumarsenidsubstrates

Kinetics and Mechanism of γ-Al2O3 Solid Phase Epitaxy on c-Plane α-Al2O3

Highly efficient terahertz generation via a continuously phase matched difference frequency generation in a nested waveguide structure