共查询到18条相似文献,搜索用时 203 毫秒
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利用MOCVD生长了不同Mg流量的P型GaN样品。研究了Mg流量对MOCVD生长的P型GaN薄膜的电学特性、表面形貌及晶体质量的影响。结果表明利用MOCVD制备高质量的P型GaN薄膜,Mg流量应处于一个合适的范围,Mg流量过低,薄膜的空穴浓度低,电学特性不好;Mg流量过高,则会产生大量的缺陷,晶体质量与表面形貌变差,Mg的活化率也降低,并且自补偿效应更加严重,最终使得空穴浓度降低,电学特性变差。将优化的条件应用于蓝光发光管的外延生长,并制备了器件,在20mA的注入电流下,输出功率为6.5mW,正向压降3V,反向击穿电压为20V。 相似文献
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利用MOCVD生长了InGaN:Mg薄膜,研究了生长温度、掺Mg量对InGaN:Mg薄膜电学特性的影响.结果表明,空穴浓度随着生长温度的降低而升高.在相同的生长温度下,空穴浓度随掺Mg量的增加,先升高后降低.通过对这两个生长条件的优化,在760℃、CP2Mg与TMGa摩尔流量之比为2.2‰时制备出了空穴浓度高达2.4×1019cm-3的p-InGaN:Mg薄膜.这对进一步提高GaN基电子器件与光电子器件的性能有重要意义. 相似文献
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利用MOCVD生长了InGaN:Mg薄膜,研究了生长温度、掺Mg量对InGaN:Mg薄膜电学特性的影响。结果表明,空穴浓度随着生长温度的降低而升高。在相同的生长温度下,空穴浓度随掺Mg量的增加,先升高后降低。通过对这两个生长条件的优化,在760°C、CP2Mg与TMGa摩尔流量之比为2.2‰时制备出了空穴浓度高达2.4×1019cm-3的p-InGaN∶Mg薄膜。这对进一步提高GaN基电子器件与光电子器件的性能有重要意义。 相似文献
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通过优化Mg流晕增强了MoCVD生长的GaN薄膜的p型电导并改善了晶体质量.Hall测量结果表明卒穴浓度首先随着Mg流量的升高而升高,达到极大值后开始降低;迁移率始终随Mg流量的升高而降低.最优的样品在室温下空穴浓度达到4.1×1017cm-3,电阻率降至1Ω·cm.考虑施主型缺陷MGaVN的自补偿作用,计算了空穴浓度随掺杂浓度变化的曲线关系.计算结果表明自补偿系数随掺杂浓度的增大而增大;空穴浓度首先随掺杂浓度的增大而增加,存受主浓度为NA≈4×1019左右时达到极大值,之后随着掺杂浓度的增大而迅速降低.XRD数据表明在实验范围内晶体缺陷密度随着掺杂浓度的降低而降低. 相似文献
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通过优化Mg流晕增强了MoCVD生长的GaN薄膜的p型电导并改善了晶体质量.Hall测量结果表明卒穴浓度首先随着Mg流量的升高而升高,达到极大值后开始降低;迁移率始终随Mg流量的升高而降低.最优的样品在室温下空穴浓度达到4.1×1017cm-3,电阻率降至1Ω·cm.考虑施主型缺陷MGaVN的自补偿作用,计算了空穴浓度随掺杂浓度变化的曲线关系.计算结果表明自补偿系数随掺杂浓度的增大而增大;空穴浓度首先随掺杂浓度的增大而增加,存受主浓度为NA≈4×1019左右时达到极大值,之后随着掺杂浓度的增大而迅速降低.XRD数据表明在实验范围内晶体缺陷密度随着掺杂浓度的降低而降低. 相似文献
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利用金属有机物化学气相沉积(MOCVD)技术在蓝宝石衬底上制备了GaN:Mg薄膜.首先,对Delta掺杂p型GaN的掺杂源流量进行优化研究,研究发现在较低46 cm3/min的CP2 Mg源流量下,晶体质量和导电性能都有所改善,获得了较高空穴浓度,为8.73×1017 cm-3,(002)和(102)面FWHM分别为245和316 arcsec.随后,采用XRD、Hall测试、PL以及AFM研究了在生长过程中加入生长停顿对Delta掺杂p型GaN材料特性的影响,发现加入生长停顿后,样品电学特性、光学特性和晶体质量并未得到改善,反而下降. 相似文献
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Wonseok Lee Jae Limb Jae-Hyun Ryou Dongwon Yoo Theodore Chung Russell D. Dupuis 《Journal of Electronic Materials》2006,35(4):587-591
We investigated the electrical and structural qualities of Mg-doped p-type GaN layers grown under different growth conditions
by metalorganic chemical vapor deposition (MOCVD). Lower 300 K free-hole concentrations and rough surfaces were observed by
reducing the growth temperature from 1,040°C to 930°C. The hole concentration, mobility, and electrical resistivity were improved
slightly for Mg-doped GaN layers grown at 930°C with a lower growth rate, and also an improved surface morphology was observed.
In0.25Ga0.75N/GaN multiple-quantum-well light emitting diodes (LEDs) with p-GaN layers grown under different conditions were also studied.
It was found from photoluminescence studies that the optical and structural properties of the multiple quantum wells in the
LED structure were improved by reducing the growth temperature of the p-layer due to a reduced detrimental thermal annealing
effect of the active region during the GaN:Mg p-layer growth. No significant difference in the photoluminescence intensity
depending on the growth time of the p-GaN layer was observed. However, it was also found that the electroluminescence (EL)
intensity was higher for LEDs having p-GaN layers with a lower growth rate. Further improvement of the p-GaN layer crystalline
and structural quality may be required for the optimization of the EL properties of long-wavelength (∼540 nm) green LEDs. 相似文献
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C. S. Kim H. K. Cho M. K. Yoo H. S. Cheong C. -H. Hong H. K. Cho 《Journal of Electronic Materials》2004,33(5):445-449
Correlation between material properties of bulk p-GaN layers grown on undoped GaN and device performance of InGaN/GaN blue
light-emitting diodes (LEDs) as a function of p-GaN growth temperature were investigated. The p-GaN layers of both structures
grown by metal-organic chemical-vapor deposition were heavily doped with Mg. As the growth temperature of the bulk p-GaN layer
increased up to 1,080°C, NA-ND increased. However, above 1,110°C, NA-ND sharply decreased, while the fluctuation of Mg concentration ([Mg]) increased. At this time, a peculiar surface, which originated
from inversion domain boundaries (IDBs), was clearly observed in the bulk p-GaN layer. The IDBs were not found in all LEDs
because the p-GaN contact layer was relatively thin. The change in photoluminescence emission from the ultraviolet band to
blue band is found to be associated with the fluctuation of [Mg] and IDBs in bulk p-GaN layers. The LED operating voltage
and reverse voltage improved gradually up to the p-GaN contact-layer growth temperature of 1,080°C. However, the high growth
temperature of 1,110°C, which could favor the formation of IDBs in the bulk p-GaN layer, yielded poorer reverse voltage and
saturated output power of the LEDs. 相似文献
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P型氮化镓退火及发光二极管研究 总被引:1,自引:0,他引:1
对金属有机物化学气相淀积(MOCVD)技术在蓝宝石衬底上生长的p型氮化镓(p-GaN)在氮气气氛下的热退火进行研究。用Hall测试系统测量不同温度、不同时间退火后样品的电学性能;对一组蓝光LEDs分别进行不同退火温度、退火时间实验,对退火前后量子阱峰值强度半高宽和积分面积变化进行了比较研究。实验表明p-GaN在825°C、8min条件下退火可以取得较高的空穴浓度,而LED在750°C、30min退火可以使量子阱的半高宽展宽较小,积分强度降低百分比小,而且LED芯片正向电压也较小。 相似文献
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MOCVD生长源流量对p型GaN薄膜特性影响的研究 总被引:1,自引:1,他引:0
利用金属有机物化学气相淀积(MOCVD)技术在蓝宝石衬底上生长p型GaN:Mg薄膜,对不同二茂镁(CP2Mg)流量和Ⅴ族和Ⅲ族摩尔(Ⅴ/Ⅲ)比生长的p型GaN:Mg薄膜特性进行研究。研究表明,增加Ⅴ/Ⅲ比,可以降低螺旋位错密度,提高p型GaN晶体质量。当Ⅴ/Ⅲ比为3 800时,Cp2Mg流量最高为170sccm,获得p型GaN(002)面峰值半高宽(FWHM)最窄为232"。同时研究发现,单纯提高Ⅴ/Ⅲ比对降低刃型位错影响较不明显。 相似文献
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The advantages of In Ga N/Ga N light emitting diodes(LEDs) with p-Ga N grown under high pressures are studied.It is shown that the high growth pressure could lead to better electronic properties of p-Ga N layers due to the eliminated compensation effect.The contact resistivity of p-Ga N layers are decreased due to the reduced donor-like defects on the p-Ga N surface.The leakage current is also reduced,which may be induced by the better filling of V-defects with p-Ga N layers grown under high pressures.The LED efficiency thus could be enhanced with high pressure grown p-Ga N layers. 相似文献
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We report the enhancement of light extraction efficiency (LEE) and electrical performance in GaN-based green light-emitting diodes (LEDs) using ZnO nanorods formed on the etched surface of p-GaN. Green LEDs with hybrid ZnO nanorod structures grown on the hexagonally etched topmost layer of the LEDs, show an improvement in electroluminescence intensity that is 3.5 times higher than LEDs without any other surface treatments. The improvement in LEE in LEDs with nanohybrid structures was confirmed by finite-difference time-domain simulation analysis. Besides LEE enhancement, the surface etching effects on the reduction of leakage current of fabricated LEDs were also investigated. 相似文献
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采用金属有机化学气相沉积技术生长了GaN基多量子阱(MQW)蓝光发光二极管外延片,并采用高分辨率X射线衍射仪(HRXRD)和光致光谱仪(PL)表征晶体质量和光学性能,其他的光电性能由制成芯片后测试获得,目的是研究外延片p型AlGaN电子阻挡层Mg掺杂的优化条件.结果表明,在生长p型AlGaN电子阻挡层的Cp2Mg流量为300 cm3/min时,蓝光发光二极管获得最小正向电压VF,而且在此掺杂流量下的多量子阱蓝光发光二极管芯片发光强度明显高于其他流量的样品.因此可以通过优化AlGaN电子阻挡层的掺杂浓度,来显著提高多量子阱蓝光发光二极管的电学性能和光学性能. 相似文献
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针对GaN基发光二极管中p-GaN与透明导电薄膜ITO之间的接触进行研究,尝试找出透明导电层ITO的优化制程条件。将在不同氧流量、ITO厚度及退火温度下制备的透明电极ITO薄膜应用于GaN基发光二极管,来增加电流扩展,减小ITO与p-GaN欧姆接触电阻,降低LED工作电压及提高透过率、增强LED发光亮度。将ITO薄膜应用于218μm×363μm GaN基发光二极管LED,分析其在20 mA工作电流条件下正向电压和光输出功率的变化,在优化条件下制得的蓝光LED在直流电流20 mA下的正向电压3.23 V,光输出效率为23.25 mW。 相似文献