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1.
Nucleation kinetics during the growth of InxGa1−xN on a GaN substrate have been studied. The behavior of nonequilibrium between the InxGa1−xN and the GaN substrate has been analyzed, and hence, the expression derived for the stress-induced supercooling/superheating
has been numerically evaluated. The maximum amount of stress-induced supercooling is found to be 1.017 K at x=0.12. These
values are incorporated in the classical heterogeneous nucleation theory. Using the regular solution model, the interfacial
tension between the nucleus and substrate and, hence, the interfacial tension between nucleus and mother phase and thermodynamical
potential of the compounds have been calculated. The amount of driving force available for the nucleation has been determined
for different compositions and degrees of supercooling. It has been shown that the value of the interaction parameter of InN-GaN
plays a dominant role in nucleation and growth kinetics of InxGa1−xN on a GaN substrate. These values have been used to evaluate the nucleation parameters. It is shown that the nucleation barrier
for the formation of a InxGa1−xN nucleus on a GaN substrate is minimum in the range of x=0.12 to x=0.17, and it has been qualitatively proved that good quality
InxGa1−xN on GaN can be grown only in the range 0<x≤0.2. 相似文献
2.
J. C. Roberts C. A. Parker J. F. Muth S. F. Leboeuf M. E. Aumer S. M. Bedair M. J. Reed 《Journal of Electronic Materials》2002,31(1):L1-L6
Metal-semiconductor-metal (MSM) photodetectors have been fabricated on InxGa1−xN epitaxial films grown by metalorganic chemical vapor deposition within the composition range 0≤x≤0.13. The dark current
and spectral response were measured for devices with a varying In mole fraction x. The devices, which had nominal finger widths
and finger spacing of 5 μm, were biased with modest voltages in the range 2≤Vbias≤5 V. In general, turn-on wave-length and dark current increased with increasing x. Turn-on wavelengths ranged from λ=370
nm to 430 nm and dark current densities ranged from Idark=2×10−2 A/cm2 (Vbias=5 V, x≈0.05) to 9×104 A/cm2 (Vbias=2 V, x≈0.13) depending on the In content, x, of the device active area. 相似文献
3.
4.
《International Journal of Hydrogen Energy》2019,44(36):19650-19657
To split water and produce hydrogen by white light is an excellent solution for the storage and supply of clean and sustainable energy. Efficiency and stability are the key challenges for a successful exploitation. InGaN, evaluated against other semiconductors, metal oxides, carbon based - and organic materials has most suited intrinsic materials properties. Based on this optimum materials choice we report photoelectrochemical (PEC) hydrogen generation under white light illumination by an InGaN-based quantum nanostructure photoelectrode. No degradation occurs for operation over 10 h. Our novel concept, combining quantum nanostructure physics with electrochemistry and catalysis leads to almost 10% efficiency at zero external voltage. The efficiency rises above 25% at 0.2 V. This is unmatched for a single photoelectrode, representing the most advanced technology of low complexity. 相似文献
5.
GaN-based blue light-emitting diodes (LEDs) on various patterned sapphire substrates (PSSs) are investigated in detail. Hemispherical and triangular pyramidal PSSs have been applied to improve the performance of LEDs compared with conventional LEDs grown on planar sapphire substrate. The structural, electrical, and optical properties of these LEDs are investigated. The leakage current is related to the crystalline quality of epitaxial GaN films, and it is improved by using the PSS technique. The light output power and emission efficiency of the LED grown on triangular pyramidal PSS with optimized fill factor show the best performance in all the samples, which indicates that the pattern structure and fill factor of the PSS are related to the capability of light extraction. 相似文献
6.
随着氮(N)面GaN材料生长技术的发展,基于N面GaN衬底的高亮度发光二极管(LED)的研究具有重要的科学意义.研究了具有高发光功率的N面GaN基蓝光LED的新型结构设计,通过在N面LED的电子阻挡层和多量子阱有源层之间插入p型InGaN/GaN超晶格来提高有源层中的载流子注入效率.为了对比N面GaN基LED优异的器件性能,同时设计了具有相同结构的Ga面LED.通过对两种LED结构的电致发光特性、有源层中能带图、电场和载流子浓度分布进行比较可以发现,N面LED在输出功率和载流子注入效率上比Ga面LED有明显的提升,从而表明N面GaN基LED具有潜在的应用前景. 相似文献
7.
Theodore Chung Jae Limb Jae-Hyun Ryou Wonseok Lee Peng Li Dongwon Yoo Xue-Bing Zhang Shyh-Chiang Shen Russell D. Dupuis David Keogh Peter Asbeck Ben Chukung Milton Feng Dimitri Zakharov Zusanne Lilienthal-Weber 《Journal of Electronic Materials》2006,35(4):695-700
The design and growth of GaN/InGaN heterojunction bipolar transistors (HBTs) by metalorganic chemical vapor deposition (MOCVD)
are studied. Atomic-force microscopy (AFM) images of p+InGaN base layers (∼100 nm) deposited under various growth conditions indicate that the optimal growth temperature is limited
to the range between 810 and 830°C due to a trade-off between surface roughness and indium incorporation. At these temperatures,
the growth pressure must be kept above 300 Torr in order to keep surface pit density under control. An InGaN graded-composition
emitter is adopted in order to reduce the number of V-shaped defects, which appear at the interface between GaN emitter and
InGaN base and render an abrupt emitter-base heterojunction nearly impossible. However, the device performance is severely
limited by the high p-type base contact resistance due to surface etching damage, which resulted from the emitter mesa etch. 相似文献
8.
We present a high momentum transfer (Q) X-ray scattering method to determine the thickness and indium composition of an InxGa1 − xN well in InGaN/GaN multiple quantum wells. At high-Q, it is demonstrated that the scattering signal from InGaN well layers is separated from that of GaN barrier layers. The structure factor of the well layers is determined from the envelope of the superlattice reflections. The thickness and the indium composition of the well layer are obtained directly from the structure factor. We discuss the high-Q analysis in comparison with the analysis of low-Q data where the scattering from InGaN well and GaN barrier interferes strongly. 相似文献
9.
Masayoshi Umeno Takashi Egawa Hiroyasu Ishikawa 《Materials Science in Semiconductor Processing》2001,4(6)
A recessed gate AlGaN/GaN high-electron mobility transistor (HEMT) on sapphire (0 0 0 1), a GaN metal-semiconductor field-effect transistor (MESFET) and an InGaN multiple-quantum well green light-emitting diode (LED) on Si (1 1 1) substrates have been grown by metalorganic chemical vapor deposition. The AlGaN/GaN intermediate layers have been used for the growth of GaN MESFET and LED on Si substrates. A two-dimensional electron gas mobility as high as 9260 cm2/V s with a sheet carrier density of 4.8×1012 cm−2 was measured at 4.6 K for the AlGaN/GaN heterostructure on the sapphire substrate. The recessed gate device on sapphire showed a maximum extrinsic transconductance of 146 mS/mm and a drain–source current of 900 mA/mm for the AlGaN/GaN HEMT with a gate length of 2.1 μm at 25°C. The GaN MESFET on Si showed a maximum extrinsic transconductance of 25 mS/mm and a drain–source current of 169 mA/mm with a complete pinch-off for the 2.5-μm-gate length. The LED on Si exhibited an operating voltage of 18 V, a series resistance of 300 Ω, an optical output power of 10 μW and a peak emission wavelength of 505 nm with a full-width at half-maximum of 33 nm at 20 mA drive current. 相似文献
10.
Growth of blue InGaN based LED structures on sapphire wafers from 2 inch to 8 inch in diameter was investigated using the Veeco K465 MOCVD platform. Our results indicate that the same pressure,rotation rate and hydride flows can be used for all wafer sizes. AFM and X-ray studies reveal that all wafer sizes have comparable high-quality crystallinity and defect levels for GaN and InGaN/GaN MQW growth. Although the larger diameter wafers exhibit larger wafer bow due to lattice and thermal mismatch,with proper ... 相似文献