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BACKGROUND: Many previous studies have explored the effects of manual massage on back muscle fatigue, and most of the mechanical massage techniques imitate manual massage. However, it is unknown whether mechanical and manual massage have the same functions for exercise-induced back muscle fatigue. OBJECTIVE: To investigate the effects of mechanical bed massage on the biochemical markers of exercise-induced back muscle fatigue in male collegiate athletes. METHODS: Twenty-eight male collegiate athletes who met the experimental criteria were recruited in this randomized controlled trial, and randomly assigned to a mechanical bed massage group (experimental group) or resting group (control group). The subjects performed eight bouts of reverse sit-up in the prone position and received 20 minutes of the intervention. Creatine kinase, blood lactate, and serum cortisol levels were measured at baseline, after fatigue, after intervention, and after 24 hours. RESULTS: The level of serum cortisol of the control group was significantly higher than that of the experimental group after the intervention (p< 0.05). The comparison of the two groups for blood lactate levels showed no significant differences at any of the measurement time-points (p> 0.05). There was no significant difference in creatine kinase levels immediately after the intervention (p> 0.05), but a significant difference in creatine kinase level was observed between the two groups 24 hours later (p< 0.05). CONCLUSIONS: Significant differences were observed between mechanical bed massage and rest condition on serum cortisol and creatine kinase for exercise-induced muscle fatigue. Therefore, mechanical bed massage may reduce stress and muscle damage for the athlete after training or competition.

Two structures of InGaN/GaN multiple quantum well solar cells are grown and fabricated in this work, which are 30 periods In0.14Ga0.86N/GaN (1.72 nm/4.14 nm, sample A) and In0.19Ga0.81N/GaN (2.76 nm/4.14 nm, sample B), respectively. The peak external quantum efficiency of sample A can reach over 60%, which is considered to be related with the longer carrier lifetime. The current density-voltage characteristics show that sample A exhibited an open-circuit voltage of 2.13 V, a short-circuit current density of 2.55 mA/cm2, a fill-factor of 65.7% and a conversion efficiency of 3.56%. Those indicators are among the best up to date as far as we know for InGaN/GaN solar cells.

In this paper, (InxAl1–xN/AlN) MQWs/InN/GaN heterostructure with a (InxAl1–xN/AlN) MQWs barrier layer and an InN channel layer is presented. The numerical calculations of 2DEG characteristics are made using a self-consistent solution of the Schrodinger and Poisson equations. The influence of (InxAl1–xN/AlN) MQWs and InN layer on band diagrams, 2DEG sheet density and carrier confinement are studied. The results show that an InN insert layer can improve the carrier-confinement ability without degrading the 2DEG sheet density in the heterostructure. The (InxAl1–xN/AlN) MQWs/InN/GaN heterostructure has both a larger 2DEG sheet density and better confinement of 2DEG than conventional InAlN/GaN and AlGaN/GaN heterojunctions. The 2DEG sheet density is as dramatically large as 3.85 × 1013 cm−2 with an AlN thickness of 1.5 nm, an In0.18Al0.82N thickness of 1.5 nm, an InN thickness of 0.5 nm, and pair number of 5. In addition, the influence of AlN thickness, InAlN thickness, indium content, and pair number on the 2DEG sheet density of the (InxAl1–xN/AlN) MQWs/InN/GaN heterostructure has been studied.

In this paper, AlGaN/GaN- and GaN/AlGaN/GaN-based Schottky barrier diodes (SBDs) were fabricated and studied for comparison. The recorded electrical characteristics of the devices show that the introduction of a GaN cap layer can evidently reduce the reverse leakage current and suppress the forward current decay of the devices. What is more important, the GaN/AlGaN/GaN-based SBDs are capable of greatly alleviating the unrecoverable degradation of the reverse characteristics, which was observed in the device without a GaN cap layer when the device was under long time reverse dc stress. Detailed analyses were discussed.

The high electron mobility transistor (HEMT) structure employing novel In x Al 1 − x N/AlN multiple-quantum-wells (MQWs) as barrier layer is presented. The two-dimensional electron gas (2DEG) characteristics of (In x Al 1 − x N/AlN)MQWs/GaN heterojunction have been investigated by solving coupled Schrodinger and Poisson equations self-consistently. The influence of AlN thickness, In x Al 1 − x N thickness, In content and pair number of (In x Al 1 − x N/AlN)MQWs on sheet carrier density is investigated. AlN thickness dependence of carriers in barrier layer to total carriers in HEMT and In 0.18 Al 0.82 N conduction band diagrams are discussed. The sheet carrier density of (In 0.18 Al 0.82 N/AlN)MQWs/GaN heterojunction is larger than that of (Al x Ga 1 − x N/GaN)SLs/GaN heterojunction and achieves to as large as 3.59 × 10 13 cm −2 with AlN thickness of 1.4 nm, barrier thickness of 15 nm and pair number of 5. The calculation shows that (In 0.18 Al 0.82 N/AlN)MQWs provide high barrier which confines the 2DEG effectively.

High electron mobility transistors (HEMTs) structures with GaN, Al0.025Ga0.975N and Al0.04Ga0.96N high resistivity (HR) buffers were grown on sapphire by metal organic chemical vapor deposition (MOCVD). The structural and electrical properties of these three samples were investigated and compared. By increasing Al composition of AlGaN buffer, full width at half maximum (FWHM) values of (0002) and (10-12) x-ray rocking curves for buffer increase, indicating higher threading dislocation density. Room temperature noncontact Hall measurements were performed, and the measured 2DEG mobility was 1828 cm2/V s for GaN buffer, 1728 cm2/V s for Al0.025Ga0.975N buffer, and 1649 cm2/V s for Al0.04Ga0.96N buffer, respectively. Combining the theoretical calculation with the experiments, it was demonstrated that the decrease of mobility was attributed to higher dislocation density in sample with higher Al composition of AlGaN buffer. Devices were fabricated and it was found that the double heterojunction (DH) HEMT with Al0.025Ga0.975N buffer could effectively reduce the buffer leakage current.

This is a theoretical study of AlGaN/AlN/GaN/AlGaN double heterojunction (DH) structure with AlGaN as buffer layer. Our calculation shows that as the buffer Al content increases, though two-dimensional electron gas (2DEG) sheet density decreases, the channel back-barrier caused by polarization-induced electric field in GaN provides better electron confinement. And under certain conditions the DH-structure shows bipolar characteristics, with an additional two-dimensional hole gas (2DHG) formed at GaN/AlGaN interface. The influence of the buffer Al content and GaN channel thickness on the 2DEG and 2DHG sheet densities are investigated, and the conditions for the disappearance of 2DHG are discussed. Also, the mobility inhibited by dislocation scattering is enhanced in DH-structure due to the enhancement of screening effect of the 2DEG.

We present numerical optimization of carrier confinement characteristics in (AlxGa1−xN/AlN)SLs/GaN heterostructures in the presence of spontaneous and piezoelectrically induced polarization effects. The calculations were made using a self-consistent solution of the Schrodinger, Poisson, potential and charge balance equations. It is found that the sheet carrier density in GaN channel increases nearly linearly with the thickness of AlN although the whole thickness and equivalent Al composition of AlxGa1−xN/AlN superlattices (SLs) barrier are kept constant. This result leads to the carrier confinement capability approaches saturation with thicknesses of AlN greater than 0.6 nm. Furthermore, the influence of carrier concentration distribution on carrier mobility was discussed. Theoretical calculations indicate that the achievement of high sheet carrier density is a trade-off with mobility.

We present calculations of carrier confinement characteristics in (Al y Ga 1− y N/AlN)SLs/GaN/(In x Ga 1− x N/GaN)MQW/GaN heterojunction structure in the presence of spontaneous and piezoelectrically induced polarization effects. The calculations were made using a self-consistent solution of the Schrodinger, Poisson, potential and charge balance equations. An optimization of In x Ga 1− x N/GaN multiquantum-well (MQW) was made firstly including thickness of GaN channel, InGaN, and indium composition of In x Ga 1− x N in order to increase carrier density and mobility, and the influence of pairs of AlGaN/AlN superlattices (SLs) and InGaN/GaN MQWs on structure was discussed. Theoretical calculations clearly indicate that the two-dimensional electron gas (2DEG) sheet carrier density in designed heterostructure is greatly increased due to the enhancing of carrier confinement compared to those in conventional AlGaN/GaN one at the similar Al composition. Furthermore, the calculated carrier distribution shows that carrier mobility will be improved by reducing interface roughness and alloy disorder scattering in designed heterostructure.

Up to 500 nm thick crack-free Al 0.25 Ga 0.75 N and Al 0.32 Ga 0.68 N epilayers have been grown on Si (1 1 1) substrates. The surface morphology of samples was investigated by an optical microscope and a scanning electron microscope (SEM). Pits and shale-like surface structure have been observed. XRD rocking curve measurements indicate the crystal quality of samples. The analyses show that the Al source flux is an important factor in growing AlGaN on Si (1 1 1). The information from the Micro-Raman spectra supported that Al atoms are gathered at nearby areas of the pits originated from the AlN/Si (1 1 1) interface in the initial stage of AlGaN growth.

Al 0.91 Ga 0.09 N epilayers have been obtained by pulsed atomic layer epitaxy (PALE) technique on sapphire (0 0 0 1) substrates. Deep ultraviolet (DUV) photoluminescence (PL) spectroscopy and Raman scattering spectrum have been employed to study the optical transitions in Al 0.91 Ga 0.09 N epilayers. We found the exciton-phonon interaction by fitting the asymmetric PL peak, in which the transverse optical phonon (TO) and the longitudinal optical (LO) phonon are the main contributor. The abnormal S-shaped temperature dependence of the PL band peak is less pronounced or has disappeared. Further analysis shows that there possibly exists a high density of deeper localized state (∼90 meV) in Al 0.91 Ga 0.09 N. The formation of these localized states provides a favorable condition for efficient light emission.

This is a theoretical study of the 1st AlN interlayer and the 2nd GaN layer on properties of the Al0.3Ga0.7N/2nd AlN/2nd GaN/1st AlN/1st GaN HEMT structure by self-consistently solving coupled Schrodinger and Poisson equations. Our calculation shows that by increasing the 1st AlN thickness from 1.0 nm to 3.0 nm, the 2DEG, which is originally confined totally in the 2nd channel, gradually decreases, begins to turn up and eventually concentrates in the 1st one. The total 2DEG (2DEG in both channels) sheet density increases nearly linearly with the increasing 1st AlN thickness. And the slope of the potential profile of the AlGaN changes with the 1st AlN thickness, causing the unusual dependence of the total 2DEG sheet density on the thickness of the AlGaN barrier. The variations of 2DEG distribution, the total 2DEG sheet density and the conduction band profiles as a function of the 2nd GaN thickness also have been discussed. Their physical mechanisms have been investigated on the basis of the surface state theory. And the confinement of 2DEG can be further enhanced by the double-AlN interlayer, compared with the InGaN back-barrier.

A single high temperature AlN (HT-AlN) buffer has been used to relieve the stress in the growth of GaN epilayers on Si (1 1 1) substrates, but the growth of crack-free GaN on Si is still difficult due to the large mismatch of the lattice and coefficient of thermal-expansion (CTE) between GaN and Si. In this paper, we report the growth of 1.2 μm thick crack-free GaN epilayers on 2 in. Si (1 1 1) substrates using the AlN sandwich structure as a buffer. The surface morphologies of the samples were observed using a microscope and AFM. Further analysis shows that the crack-free sample is closely correlated to the introduction of the AlN sandwich structure as the buffer. To better understand the relationship between the cracks and the stress, Raman scattering has been used to study the stress in the samples. The results indicate that the sandwich structure with top AlN and bottom AlN can more effectively accommodate the strain energy caused by CTE mismatch stress.

In this work, the structure of InxGa1−xN/GaN quantum dots solar cell is investigated by solving the Schrodinger equation in light of the Kronig–Penney model. Compared to p–n homojunction and heterojunction solar cells, the InxGa1−xN/GaN quantum dots intermediate band solar cell manifests much larger power conversion efficiency. Furthermore, the power conversion efficiency of quantum dot intermediate band solar cell strongly depends on the size, interdot distance and gallium content of the quantum dot arrays. Particularly, power conversion efficiency is preferable with the location of intermediate band in the middle of the potential well.

Crack-free GaN epitaxial layer was obtained through inserting 80 nm graded AlGaN buffer layer between GaN epilayer and high temperature AlN buffer on 2-in Si(111) substrates by metal organic chemical vapor deposition. This paper investigated the influence of AlGaN buffer thickness on the structural properties of the GaN epilayer. It was confirmed from the optical microscopy and scanning electronic microscopy that the graded AlGaN buffer with optimized thickness had a remarkable effect on introducing relative compressive strain to the top GaN layer and preventing the formation of cracks. X-ray diffraction and atomic force microscopy analysis showed that AlGaN buffer with proper thickness could improve the crystal quality and surface morphology of the GaN film. Transmission electron microscopy analysis revealed that a significant reduction in threading dislocations was achieved in GaN epilayer by the insertion of graded AlGaN buffer.

The AlxGa1 − xN/AlyGa1 − yN multiple quantum well (MQW) structure for deep ultraviolet emission has been grown on sapphire by metal organic chemical vapor deposition (MOCVD). High resolution X-ray diffraction (HRXRD), atomic force microscopy (AFM), and cathodoluminescence (CL) are used to characterize the structural and optical properties of MQWs, respectively. Clear step flows can be observed in the AFM image indicating a two-dimensional growth model. There are many cracks on the surface of the MQW structure because of the high tensile stress. HRXRD shows multiple satellite peaks to the 2nd order. The HRXRD simulation shows that the MQW period is about 11.5 nm. The emission peak of AlxGa1 − xN/AlyGa1 − yN MQWs is about 295 nm in the deep ultraviolet region from the CL spectra.

AlxGa1-xN ternary alloys are very attractive materials for application to ultraviolet (UV) photodetection. In this work, high Al content AlxGa1-xN films are grown on sapphire substrate by low pressure metalorganic chemical vapor deposition (MOCVD). The Al content in the AlxGa1-xN epilayer is estimated to be 54% by high resolution X-ray diffraction (HRXRD) and Vegard’s law. The full width at half maximum (FWHM) of the rocking curve for the Al0.54Ga0.46N (0002) is about 597 arcsec. According to the transmittance measurement result, our sample is suitable for fabricating solar-blind photodetectors. The observed Fabry-Perot fringes in the transmission region indicate that high optical quality is obtained. Solarblind metal-semiconductor-metal (MSM) photodetectors based on the MOCVD-grown Al0.54Ga0.46N film are fabricated and tested. The detector has a low dark current of about 31 pA under a bias voltage of 5 V. An UV/visible contrast of about four orders of magnitude is observed and responsivity increases with increments of the bias voltage.

The effect of thickness of the high-temperature (HT) AlN buffer layer on the properties of GaN grown on Si(111) has been investigated. Optical microscopy (OM), atomic force microscopy (AFM) and X-ray diffraction (XRD) are employed to characterize these samples grown by metal-organic chemical vapor deposition (MOCVD). The results demonstrate that the morphology and crystalline properties of the GaN epilayer strongly depend on the thickness of HT AlN buffer layer, and the optimized thickness of the HT AlN buffer layer is about 110nm. Together with the low-temperature (LT) AlN interlayer, high-quality GaN epilayer with low crack density can be obtained.

We investigate the growth temperature dependences of InN films grown by metal organic chemical vapor deposition (MOCVD). Experimental results indicate that growth temperature has a strong effect on the surface morphology, crystalline quality and electrical properties of the InN layer. The increasing growth temperature broadened the v scan's full-width at half-maximum (FWHM) and roughened the surface morphology; whereas the electrical properties improved: As the temperature increased from 460 degrees C to 560 degrees C, room-temperature Hall mobility increased from 98 cm(2)/V s to nearly 800 cm(2)/V s and carrier concentration dropped from 5.29 x 10(19) cm (3) to 0.93 x 10(19) cm (3). The higher growth temperature resulted in more efficient cracking of NH3, which improved Hall mobility and decreased carrier concentration. (C) 2008 Elsevier B.V. All rights reserved.

AlGaN/GaN high electron mobility transistor (HEMT) hetero-structures were grown on the 2-in Si (111) substrate using metal-organic chemical vapor deposition (MOCVD). Low-temperature (LT) AlN layers were inserted to relieve the tension stress during the growth of GaN epilayers. The grown AlGaN/GaN HEMT samples exhibited a maximum crack-free area of 8mmx5mm, XRD GaN (0002) full-width at half-maximum (FWHM) of 661arcsec and surface roughness of 0.377nm. The device with a gate length of [email protected] and a gate width of [email protected] demonstrated maximum drain current density of 304mA/mm, transconductance of 124mS/mm and reverse gate leakage current of [email protected]/mm at the gate voltage of -10V.

Low temperature (LT) AlN interlayers were used to effectively reduce the tension stress and micro-cracks on the surface of the GaN epilayer grown on Si (111) substrate. Optical Microscopy (OM), Atomic Force Microscopy (AFM), Surface Electron Microscopy (SEM) and X-Ray Diffraction (XRD) were employed to characterize these samples grown by metal-organic chemical vapor deposition (MOCVD). In addition, wet etching method was used to evaluate the defect of the GaN epilayer. The results demonstrate that the morphology and crystalline properties of the GaN epilayer strongly depend on the thickness, interlayer number and growth temperature of the LT AlN interlayer. With the optimized LT AlN interlayer structures, high quality GaN epilayers with a low crack density can be obtained. (C) 2008 Elsevier Ltd. All rights reserved.

The sheet carrier concentrations, conduction band profiles and amount of free carriers in the barriers have been determined by solving coupled Schrodinger and Poisson equation self-consistently for coherently grown Al"0"."3Ga"0"."7N/GaN and Al"0"."3Ga"0"."7N/AlN/GaN structures on thick GaN. The Al"0"."3Ga"0"."7N/GaN heterojunction structures with and without 1nm AlN interlayer have been grown by MOCVD on sapphire substrate, the physical properties for these two structures have been investigated by various instruments such as Hall measurement and X-ray diffraction. By comparison of the theoretical and experimental results, we demonstrate that the sheet carrier concentration and the electrons mobility would be improved by the introduction of an AlN interlayer for Al"0"."3Ga"0"."7N/GaN structure. Mechanisms for the increasing of the sheet carrier concentration and the electrons mobility will be discussed in this paper.

InGaN photovoltaic structures with p-n junctions have been fabricated by metal organic chemical vapour deposition. Using double-crystal X-ray diffraction measurements, it was found that the room temperature band gaps of p-InGaN and n-InGaN films were 2.7 and 2.8 eV, respectively. Values of 3.4 x 10(-2) mA cm(-2) short-circuit current, 0.43 V open-circuit voltage and 0.57 fill factor have been achieved under ultraviolet illumination (360 nm), which were related to p-n junction connected back-to-back with a Schottky barrier and many defects of the p-InGaN film. 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enhancement of the electrical properties in an AlGaN/GaN high electron mobility transistor (HEMT) structures was demonstrated by employing the combination of a high mobility GaN channel layer and an AlN interlayer. The structures were grown on 50 mm semi-insulating (SI) 6H-SiC substrates by metalorganic chemical vapor deposition (MOCVD). The room temperature (RT) two-dimensional electron gas (2DEG) mobility was as high as 2215 cm(2)/V s, with a 2DEG concentration of 1.044 x 10(13)cm(-2). The 50 mm HEMT wafer exhibited a low average sheet resistance of 251.0 Omega/square, with a resistance uniformity of 2.02%. The 0.35 Pin gate length HEMT devices based on this material structure, exhibited a maximum drain current density of 1300 mA/mm, a maximum extrinsic transconductance of 314 mS/mm, a current gain cut-off frequency of 28 GHz and a maximum oscillation frequency of 60 GHz. The maximum output power density of 4.10 W/mm was achieved at 8 GHz, with a power gain of 6.13 dB and a power added efficiency (PAE) of 33.6%. (c) 2006 Elsevier B.V. All rights reserved.

In undoped high-resistivity GaN epilayers grown by metalorganic chemical vapor deposition (MOCVD) on sapphire, deep levels are investigated by persistent photoconductivity (PPC) and optical quenching (OQ) of photoconductivity (PC) measurements. The PPC and OQ are studied by exciting the samples with two beams of radiation of various wavelengths and intensities. When the light wavelengths of 300 and 340 nm radiate the GaN epilayer, the photocurrent without any quenching effect is rapidly increased because the band gap transition only occurs. If the background light is 340 nm and the quenching light is 564 or 828 nm, the quenching of a small photocurrent generates but clearly. Two broad quenching bands that extend from 385 to 716 nm and from 723 to 1000 nm with a maximum at approximately 2.2 eV (566 nm) is observed. These quenching bands are attributed to hole trap level's existence in the GaN epilayer. We point out that the origin of the defects responsible for the optical quenching can be attributed to nitrogen antisite and/or gallium vacancy. (c) 2006 Elsevier B.V. All rights reserved.

Unintentionally doped high-Al-content Al0.45Ga0.55N/GaN high electron mobility transistor (HEMT) structures with and without AlN interfacial layer were grown by metal-organic chemical vapor deposition (MOCVD) on two-inch sapphire substrates. The effects of AlN interfacial layer on the electrical properties were investigated. At 300 K, high two-dimensional electron gas (2DEG) density of 1.66 x 10(11) cm(-2) and high electron mobility of 1346 cm(2) V-1 s(-1) were obtained for the high Al content HEMT structure with a 1 nm AlN interfacial layer, consistent with the low average sheet resistance of 287 Omega/sq. The comparison of HEMT wafers with and without AlN interfacial layer shows that high Al content AlGaN/AlN/GaN heterostructures are potential in improving the electrical properties of HEMT structures and the device performances. (c) 2006 Elsevier B.V. All rights reserved.

Al0.38Ga0.62N/AIN/GaN HEMT structures have been grown by metal-organic chemical vapor deposition (MOCVD) on 2-inch sapphire substrates. Samples with AIN growth time of 0s (without AIN interlayer), 12, 15, 18 and 24s are characterized and compared. The electrical properties of two-dimensional electron gas (2DEG) are improved by introducing AIN interlayers. The AIN growth time in the range of 12-18s, corresponding to the AIN thickness of 1-1.5 nm, is appropriate for the design of Al0.38Ga0.62N/AIN/GaN HEMT structures. The lowest sheet resistance of 277 Omega sq(-1) and highest room temperature 2DEG mobility of 1460 cm(2)V(-1) s(-1) are obtained on structure with AIN growth time of 12s. The structure with AIN growth time of 15s exhibits the highest 2DEG concentration of 1.59 x 10(13) cm(-2) and the smallest RMS surface roughness of 0.2 nm. (c) 2006 Elsevier B.V. All rights reserved.

Undoped high resistivity (HR) GaN epilayers were grown on (0001) sapphire substrate by metalorganic chemical vapor deposition (MOCVD). Thermally stimulated current (TSC) and resistivity measurements have been carried out to investigate deep level traps. Deep levels with activation energies of 1.06eV and 0.85eV were measured in sample 1. Gaussian fitting of TSC spectra showed five deep levels in different samples. (c) 2006 WILEY VCH Vertag GmbH & Co. KGaA, Weinheim

Al0.3Ga0.7N/AlN/GaN HEMT structures with significantly high mobility have been grown by metalorganic chemical vapor deposition (MOCVD) on sapphire substrates. At room temperature (RT) a Hall mobility of 2104 cm(2)/Vs and a two-dimensional electron gas (2DEG) density of 1.1x10(13) cm(-2) are achieved, corresponding to a sheet resistance of 277.8 Omega/sq. The elimination of V-shaped defects were observed on Al0.3Ga0.7N/AlN/GaN HEMT structures and correlated with the increase of 2DEG mobility. (c) 2006 WILEY-VCH Verlag GmbH & Co KGaA, Weinheim.

Improved electrical properties of AlxGa1-xN/GaN high electron mobility transistor (HEMT) structures grown by metalorganic chemical vapor deposition (MOCVD) were achieved through increasing the Al mole fraction in the AlGaN barrier layers. An average sheet resistance of 326.6 Omega/sq and a good resistance uniformity of 98% were obtained for a 2-inch Al0.38Ga0 62N/GaN HEMT structure. The surface morphology of AlxGa1-xN/GaN HEMT structures strongly correlates with the Al content. More defects were formed with increasing Al content due to the increase of tensile strain, which limits further reduction of the sheet resistance. (c) 2006 WILEY-VCH Verlag GmbH & Co KGaA, Weinheim.

Synthesizing hexagonal wurtzite GaN nanowires involves nitriding Ga2O3 films, which deposited on GaAs(1 1 0) substrates with electrophoresis. The cylindrical structures of GaN nanowires with the diameters ranging from 40 to 200 nm and lengths up to over 100 μm have been obtained. Scanning electron microscopy (SEM) images showed the morphologies of the one-dimensional single crystal materials containing straight and curved nanowires. GaN spherical crystals attached to the fibers with diameters about 600 nm were detected for the first time. The synthesis of one-dimensional GaN nanowires can be achieved without assistance of a template of a catalyst.