GaN-based, mushroom-shaped microdisk lasers were fabricated using band-gap selective photoelectrochemical etching. The optically pumped microdisks had well-defined, distinct modes at excitation powers ranging from about 8to16W∕cm2. Modal linewidths of 0.09nm reported, which was near the resolution measurement equipment. Quality factors for >4600. observed lasing threshold 12.1W∕cm2. At higher powers, heating effects and degradation in optical response microdisks.

GaN-based photonic-crystal membrane nanocavities with Q factors up to 800 have been realized at the wavelength of ∼480nm. The tuning behavior agrees well numerical calculations using finite-difference time-domain method. Theoretically, lowest energy mode a cavity that consists seven missing holes in Γ-K direction promises factor as high 4×104 volume about 1.3×(λ∕n)3.

A facile, site-specific viral-templated assembly method was used to fabricate sensitive hydrogen sulfide (H2S) gas sensors at room temperature. gold-binding M13 bacteriophage served organize gold nanoparticles into linear arrays which were as seeds for subsequent nanowire formation through electroless deposition. Nanowire widths and densities within the modified by deposition time phage concentration, respectively, tune device resistance. Chemiresistive H2S with superior temperature sensing...

Microorganisms (e.g., bacteria, fungi, and viruses) add indispensable functionality to a range of electrospun polymer materials devices. The optimal distribution bioactive agents on either the interior or exterior fiber is application-specific. Current microbe surface immobilization strategies core-confinement techniques continue pose number challenges. Here, we explore simple strategy, utilizing electrostatic forces, control migration concentration M13 bacteriophage within near-field...

A three-period vertically oriented GaN-based air-gap distributed Bragg reflector structure was fabricated using band-gap-selective photoelectrochemical (PEC) etching. The epitaxial consisted of an Al0.08Ga0.92N∕(In0.04Ga0.96N∕In0.07Ga0.93N) superlattice structure, wherein the InGaN layers served as sacrificial during PEC Microreflectance measurements yielded average enhancement in reflected signal ∼12-fold over wavelength range 550–650 nm, when compared with from a dry-etched GaN surface.

Photonic crystal membrane cavities play a key role as building blocks in the realization of several applications, including quantum information and photonic circuits. Thus far, there has been no work on defect with active layers emitting UV to green range spectrum based (Al,In,Ga)N material system. While this system great potential for new generation optoelectronic devices, are obstacles fabrication GaN-based cavities, absence conventional selective chemical wet etch. Here, we demonstrate...

We report on band-gap-selective photoelectrochemical (PEC) etching of thick InGaN layers for use in optical devices, such as GaN microdisks, distributed Bragg reflectors, and two-dimensional photonic crystal membranes. Three sacrificial layer structures are studied: a 300nm layer, an InGaN∕GaN superlattice, InGaN∕InGaN superlattice. Calculated equilibrium band diagrams the epitaxial used to explain observed behavior. The strong piezoelectric-induced fields within found greatly affect carrier...

With the emergence of multidrug-resistant bacteria, photothermal therapy has been proposed as an alternative to antibiotics for targeting and killing pathogens. In this study, two M13 bacteriophage polymorphs were studied nanoscaffolds plasmonic bactericidal agents. Receptor-binding proteins found on pIII minor coat protein targeted Escherichia coli bacteria with F-pili (F+ strain), while a gold-binding peptide motif displayed pVIII major templated Au nanoparticles. Temperature-dependent...

An effective gate recess etch process has been applied to AlGaN/GaN modulation-doped field-effect transistors (MODFETs), utilizing low power Cl2 reactive ion etching. In comparison GaAs-based materials, GaN shows a greater robustness damage under bombardment at very energies (<70 V). It suggests that viable is possible. Recessed MODFETs with drain breakdown higher than −80 V have demonstrated an optimized lower

One-dimensional gold/polypyrrole (Au/PPy) nanopeapods were fabricated using a viral template: M13 bacteriophage. The genetically modified filamentous virus displayed gold-binding peptides along its length, allowing selective attachment of gold nanoparticles (Au NPs) under ambient conditions. A PPy shell was electropolymerized on the viral-templated Au NP chains forming nanopeapod structures. morphology and thickness controlled through electrodeposition potential time, resulting in an...

Whispering gallery mode (WGM) resonators demonstrate great potential for photonic and sensing applications. Yet, these devices are often disadvantaged by costly materials or complex fabrication approaches, in addition to lack of manufacturing scalability. Near-field electrospinning (NFES), a recently emerged facile fiber method, offers solution. Here, WGM resonances reported Rhodamine 6G-doped poly(vinyl) alcohol (PVA) microfibers via NFES. Diameters tuned over range more than 10 μm varying...

The growth of crystalline copper sulfide using a viral template was investigated sequential incubation in CuCl2 and Na2S precursors. Non-specific electrostatic attraction between genetically-modified M13 bacteriophage cations the precursor caused phage agglomeration bundle formation. Following addition Na2S, polydisperse nanocrystals 2-7 nm size were found along length scaffold. structure material identified as cubic anti-fluorite type Cu1.8S, space group Fm3[overline]m. Strong interband...

A gold-binding filamentous virus was converted to its spheroidal form and investigated as a versatile template of nanostructure formation.

Etch damage of GaN was investigated using a quantum-well probe structure. A clear decrease in photoluminescence (PL) intensity observed and aggravated with increasing ion-beam voltage. The magnitude PL much larger than expected, even greater for GaAs subjected to similar etch conditions. Angle-dependent bombardment studies were carried out investigate channeling as mechanism GaN. large near normal incidence or along the [0001] direction suggests that is low-energy

Gold-palladium (Au-Pd) nanopeapod-based H2 chemiresistors were fabricated using a gold binding M13 viral template. Peptides displayed along the length of this biological template served as affinity sites to direct nanoparticle assembly under ambient conditions in an aqueous environment. In addition, geometry filamentous biomolecule readily facilitated formation highly anisotropic nanopeapod structure. Pd electroless deposition controlled peapod diameter, well electrical resistance. Sensor...

Hybrid films of bio-templated gold nanowires and chemical bath deposited nanocrystalline CdSe were fabricated. The conductivity the within hybrid material was controlled by electroless deposition. Photocurrent measurements taken on nanowire films, films. incorporation clearly increased extraction photogenerated carriers CdSe. showed a direct correlation with conductivity.

Although GaN is a chemically inert, thermally stable material, it has demonstrated sensitivity to ion damage generated by dry etch processes such as reacting etching and inductively coupled plasma etching. Recombination-enhanced diffusion an important mechanism which been observed in other III–V semiconductor systems. In this study we examine the possibility of enhanced using quantum well (QW) probe structures. The deeper QWs (750 1000 Å deep) showed steady decrease relative...

The optical and electrical stabilities of viral-templated non-stoichiometric copper sulfide, digenite (Cu1.8S) films were investigated. composed large agglomerates randomly aligned Cu1.8S-coated M13 filamentous phage. Free carrier absorption associated with localized surface plasmon resonance (LSPR) was observed in the near infrared spectral region, electrically active, displaying a linear current-voltage relationship. Under ambient conditions, magnitude LSPR increased, following power law...

III-nitride microdisks with InGaN multiple quantum well active regions were fabricated using photoelectrochemical etching. The thin, mushroom-shaped devices smooth undercut surfaces. High quality optical modes observed. A focused ion beam was used to further polish the microdisk sidewalls, as study effect of damage gain region microdisk. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Copper sulfide-based ammonia (NH3) gas sensors were assembled using a genetically modified viral template. Glutamic acid residues on the filament-shaped bioscaffold surface facilitated synthesis of nanocrystalline Cu1.8S. Each device comprised network biological materials decorated with nonstoichiometric semiconductor. These chemiresistive devices had high sensitivity to NH3 concentrations from 10 80 ppm under room-temperature operation. Response times greater than 15 min observed. results...

Preliminary studies toward the assembly of a gold-polypyrrole (PPy) peapod-like chemiresistive ammonia (NH3) gas sensors are presented. The proposed synthesis process will use electropolymerization to embed gold nanoparticles in polypyrrole nanowires. Viral-templating and PPy electrodeposition via cyclic voltammetry focus this investigation. A gold-binding M13 bacteriophage was used as bio-template assemble continuous chains on interdigitated Pt working electrodes. dimensions resulting...