Blue Diode Lasers

Johnson, N. M.; Nurmikko, A. V.; DenBaars, Steven P.

doi:10.1063/1.1325190

Cited by 77 publications

(47 citation statements)

References 10 publications

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“…[18] The magnitude of the band gap can be adjusted to match the conduction band edges of InN and TiO 2 by doping with Ga, for example, to form an In x Ga 1Àx N alloy, [19,20] or by doping TiO 2 with nitrogen to form TiO 2Àx N x . [21,22] The growth of InN films has been performed on silicon substrates, [23] sapphire, GaN, and GaAs.…”

mentioning

confidence: 99%

Low‐Pressure Organometallic Chemical Vapor Deposition of Indium Nitride on Titanium Dioxide Nanoparticles

Wang

Lin

2004

ChemPhysChem

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The photophysics of titanium dioxide (TiO 2 ) sensitized by dyes, [1,2] polymers, [3,4] and semiconductors [5,6] has been widely studied with an aim of solar energy conversion by the photovoltaic effect. These potential sensitizers have to have a suitable band gap, to absorb sunlight efficiently, and a proper conduction band edge, to transfer light-excited electrons to TiO 2 rapidly. Dye-sensitized TiO 2 photovoltaic solar cells (the socalled Grätzel-type solar cell), which exhibit an energy conversion efficiency of around 10 %, were successfully pioneered by Grätzel and co-workers. [1,2,7] However, dyes are relatively expensive, [8] and organic compounds have shorter lifetimes and are less stable than inorganic materials, for example, when used as semiconductors. Among these semiconductors, quantum-dotsensitized TiO 2 nanoparticles (sensitized by InP, PbS, CdS, Ag 2 S) have been well-examined [5,6] and showed the evidence of electron transfer from the quantum dots into the TiO 2 . Indium nitride is another candidate for this type of semiconductor-sensitized TiO 2 system. Based on a model calculation, the conversion efficiency of InN/Si tandem films could reach as much as 32 % at AM = 1.5, [9] where AM, air mass, is a large body of air with similar temperature and moisture properties throughout. Therefore, nanocrystalline TiO 2 films with an extremely large surface-to-volume ratio of InN/TiO 2 tandem films may be considered as potential candidates for photovoltaic applications.InN, a well-characterized III-V semiconductor with a stable wurtzite crystal structure, [10] has been used for visible optoelectronics and high-efficiency solar cell applications. [11][12][13] This chemically stable and robust InN has a useful range of band gaps, 0.7-2.1 eV, [14][15][16][17][18] which result from the crystallinity [16] and quantum confinement effects.[18] The magnitude of the band gap can be adjusted to match the conduction band edges of InN and TiO 2 by doping with Ga, for example, to form an In x Ga 1Àx N alloy, [19,20] or by doping TiO 2 with nitrogen to form TiO 2Àx N x . [21,22] The growth of InN films has been performed on silicon substrates, [23] sapphire, GaN, and GaAs. [24][25][26] Various methods have been used including organometallic chemical vapor deposition (OMCVD), [27][28][29] laser-assisted OMCVD, [23] magnetron sputtering, [30,31] molecular beam epitaxy (MBE), [14,16] and halogen-transport vapor-phase epitaxy.[32] In conventional OMCVD deposition on standard substrates, trimethyl indium (TMIn) has been used as the most efficient indium precursor, [15,18,23] and hydrazoic acid (HN 3 ) is the most efficient nitride precursor. [18,23] The objective of this Communication is to demonstrate the deposition of high-quality InN films onto TiO 2 nanoparticles using TMIn and HN 3 by low-pressure OMCVD for the first time. The deposited InN films were analyzed by X-ray powder diffractometry (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and UV/Vis spectroscopy. Figure 1 shows two XRD patterns ...

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confidence: 99%

Low‐Pressure Organometallic Chemical Vapor Deposition of Indium Nitride on Titanium Dioxide Nanoparticles

Wang

Lin

2004

ChemPhysChem

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“…GaN is a preferred material for optoelectronic devices such as blue-violet and UV lightemitting diodes (LEDs) and lasers [1,2]. Effective p-type doping of GaN has been a significant challenge for the fabrication of efficient devices with long operating lifetime.…”

Section: Introductionmentioning

confidence: 99%

Vibrational Spectroscopy of GaN:Mg Under Pressure

et al. 2001

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The microscopic structure of Mg-H complexes in GaN has been a subject of intense theoretical and experimental investigation. In order to probe the Mg-H structure, we have studied the effect of hydrostatic pressure on the local vibrational mode (LVM) frequency. At ambient pressure, the LVM frequency is 3125 cm -1 , which corresponds to a N-H stretching mode. In this study, Fourier-transform spectroscopy was performed on free-standing GaN:Mg,H samples in a diamond-anvil cell, with nitrogen as a pressure-transmitting fluid. The samples had been removed from their sapphire substrate by the laser-liftoff technique. The LVM frequency was measured, at liquid helium temperatures, for pressures ranging from 0 to 5 GPa. The pressure dependence of the frequency is nonlinear: first it decreases with pressure, then it increases. Comparison with first-principles calculations allows us to derive information about the microscopic structure of the Mg-H complex. The calculated stable configuration indeed gives rise to a frequency shift consistent with experiment. Based on the comparison between theory and experiment, we can exclude the bond-center configuration, which would result in a much larger pressure derivative than experimentally observed.

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“…In a general article in Physics Today, issue of October 2000 [103], it was stated that: "The recent achievement of compact blue-emitting gallium nitride semiconductor lasers is likely to have far-reaching technological and commercial effects. The lasers' short wavelengths -around 400 nm, half that of gallium arsenide-based lasers, permit higher spatial resolution in applications such as optical storage and printing.…”

Section: Nonlinear Transport In Highly-polar Semiconductorsmentioning

confidence: 99%

The role of nonequilibrium thermo-mechanical statistics in modern technologies and industrial processes: an overview

Rodrigues¹,

Silva²,

Silva³

et al. 2010

Braz. J. Phys.

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The nowadays notable development of all the modern technology, fundamental for the progress and well being of world society, imposes a great deal of stress in the realm of basic Physics, more precisely on ThermoStatistics. We do face situations in electronics and optoelectronics involving physical-chemical systems farremoved-from equilibrium, where ultrafast (in pico-and femto-second scale) and non-linear processes are present. Further, we need to be aware of the rapid unfolding of nano-technologies and use of low-dimensional systems (e.g., nanometric quantum wells and quantum dots in semiconductor heterostructures). All together this demands having an access to a Statistical Mechanics being efficient to deal with such requirements. It is worth noticing that the renowned Ryogo Kubo once stated that "statistical mechanics has been considered a theoretical endeavor. However, statistical mechanics exists for the sake of the real world, not for fictions. Further progress can only be hoped by close cooperation with experiment". Moreover, one needs to face the study of soft matter and fluids with complex structures (usually of the average self-affine fractal-like type). This is relevant for technological improvement in industries like, for example, that of polymers, petroleum, cosmetics, food, electronics and photonics (conducting polymers and glasses), in medical engineering, etc. It is then required to introduce a thermo-hydrodynamics going well beyond the classical (Onsagerian) one. Moreover, in the both type of situations above mentioned there often appear difficulties of description and objectivity (existence of so-called "hidden constraints"), which impair the proper application of the conventional ensemble approach used in the general, logically and physically sound, and well established Boltzmann-Gibbs statistics. A tentative to partially overcome such difficulties consists in resorting to non-conventional approaches. Here we briefly describe the construction of a Non-Equilibrium Statistical Ensemble Formalism (NESEF) that can deal, within a certain degree of success, with the situations above described. Several particular instances involving experimental observations and measurements in the area of semiconductor physics and in physics of fluids, which were analyzed in the context of the theory, are summarized. They comprise the cases of ultrafast optical spectroscopy; optical and transport processes in low-dimensional complex semiconductors; nonlinear transport in doped highly-polar semiconductors (of use in "blue diodes") under moderate to high electric fields; nonlinear higher-order thermo-hydrodynamics in fluids under driven flow, in normal solutions and in complex situations as in solutions of polymers, micelles, DNA, and in microbatteries.

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Blue Diode Lasers

Cited by 77 publications

References 10 publications

Low‐Pressure Organometallic Chemical Vapor Deposition of Indium Nitride on Titanium Dioxide Nanoparticles

Low‐Pressure Organometallic Chemical Vapor Deposition of Indium Nitride on Titanium Dioxide Nanoparticles

Vibrational Spectroscopy of GaN:Mg Under Pressure

The role of nonequilibrium thermo-mechanical statistics in modern technologies and industrial processes: an overview

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