排序方式: 共有63条查询结果,搜索用时 15 毫秒
41.
42.
研究了GaN基p-i-n(p-AlGaN/i-GaN/n-GaN)结构紫外探测器的漏电机理.实验发现,在位错密度几乎相同的情况下,基于表面有较高密度的V形坑缺陷材料制备的器件表现出较高的反向漏电.进一步的SEM测试发现,这种V形坑穿透到有源区i-GaN、甚至n-GaN层.在制备p-AlGaN电极时,许多金属会落在V形坑中,从而与i-GaN形成了肖特基接触,有些甚至直接和n-GaN形成欧姆接触.正是由于并联的肖特基接触和欧姆接触的存在导致了漏电的增加.
关键词:
GaN
紫外探测器
V形坑
反向漏电 相似文献
43.
研究了GaN肖特基结构(n--GaN /n+-GaN)紫外探测器的结构参数对器件性能的影响机理。模拟计算结果表明:提高肖特基势垒高度和减小表面复合速率,不仅可以增加器件的量子效率,而且可以极大地减小器件的暗电流;适当地增加n--GaN层厚度和载流子浓度可以提高器件的量子效率,但减小n--GaN层的载流子浓度却有利于减小器件的暗电流。我们针对实际应用的需要,提出了一个优化器件结构参数的设计方案,特别是如果实际应用中对器件的量子效率和暗电流都有较高的要求,肖特基势垒高度应该≥0.8 eV,n--GaN层的厚度≥200 nm,载流子浓度1×1017 cm-3 左右,表面复合速率<1×107 cm/s。 相似文献
44.
A method for accurate determination of the curvature radius of semiconductor thin films is proposed. The curvature-induced broadening of the x-ray rocking curve (XRC) of a heteroepitaxially grown layer can be determined if the dependence of the full width at half maximum (FWHM) of XRC is measured as a function of the width of incident x-ray beam. It is found that the curvature radii of two GaN films grown on a sapphire wafer are different when they are grown under similar MOCVD conditions but have different values of layer thickness. At the same time, the dislocation-induced broadening of XRC and thus the dislocation density of the epitaxial film can be well calculated after the curvature correction. 相似文献
45.
46.
Metal-semiconductor-metal ultraviolet photodetector based on GaN 总被引:1,自引:0,他引:1
A metal-semiconductor-metal (MSM) ultraviolet photodetector has been fabricated using unintentionally doped n-GaN films grown on sapphire substrates. Its dark current, photocurrent under the illumination with λ = 360 nm light, responsivity, and the dependence of responsivity on bias voltage were measured at room temperature. The dark current of the photodetector is 1.03 Na under 5 V bias, and is 15.3 Na under 10 V bias. A maximum responsivity of 0.166 A/W has been achieved under the illumination with λ= 366 nm light and 15 V bias. It exhibits a typical sharp band-edge cutoff at the wavelength of 366 nm, and a high responsivity at the wavelength from 320 nm to 366 nm. Its responsivity under the illumination with λ= 360 nm light increases when the bias voltage increases. 相似文献
47.
Output light power of InGaN-based violet laser diodes improved by using a u-InGaN/GaN/AlGaN multiple upper waveguide 下载免费PDF全文
The upper waveguide(UWG) has direct influences on the optical and electrical characteristics of the violet laser diode(LD) by changing the optical field distribution or barrier of the electron blocking layer(EBL). In this study, a series of In GaN-based violet LDs with different UWGs are investigated systematically with LASTIP software. It is found that the output light power(OLP) under an injecting current of 120 mA or the threshold current(Ith) is deteriorated when the UWG is u-In_(0.02)Ga_(0.98)N/GaN or u-In_(0.02)Ga_(0.98)N/Al_xGa_(1-x)N(0 ≤ x ≤ 0.1), which should be attributed to small optical confinement factor(OCF) or severe electron leakage. Therefore, a new violet LD structure with u-In_(0.02)Ga_(0.98)N/GaN/Al_(0.05)Ga_(0.95)N multiple layer UWG is proposed to reduce the optical loss and increase the barrier of EBL. Finally,the output light power under an injecting current of 120 mA is improved to 176.4 mW. 相似文献
48.
Different variation behaviors of resistivity for high-temperature-grown and low-temperature-grown p-GaN films 下载免费PDF全文
Two series of p-GaN films grown at different temperatures are obtained by metal organic chemical vapor deposition(MOCVD). And the different variation behaviors of resistivity with growth condition for high- temperature(HT)-grown and low-temperature(LT)-grown p-GaN films are investigated. It is found that the resistivity of HT-grown p-GaN film is nearly unchanged when the NH_3 flow rate or reactor pressure increases. However, it decreases largely for LT-grown p-GaN film.These different variations may be attributed to the fact that carbon impurities are easy to incorporate into p-GaN film when the growth temperature is low. It results in a relatively high carbon concentration in LT-grown p-GaN film compared with HT-grown one. Therefore, carbon concentration is more sensitive to the growth condition in these samples, ultimately,leading to the different variation behaviors of resistivity for HT- and LT-grown ones. 相似文献
49.
Room-Temperature Continuous-Wave Operation of InGaN-Based Blue-Violet Laser Diodes with a Lifetime of 15.6 Hours 下载免费PDF全文
We report our recent progress of investigations on InGaN-based blue-violet laser diodes (LDs). The roomtemperature (RT) cw operation lifetime of LDs has extended to longer than 15.6 h. The LD structure was grown on a c-plane free-standing (FS) GaN substrate by metal organic chemical vapor deposition (MOCVD). The typical threshold current and voltage of LD under RT cw operation are 78 mA and 6.8 V, respectively. The experimental analysis of degradation of LD performances suggests that after aging treatment, the increase of series resistance and threshold current can be mainly attributed to the deterioration of p-type ohmic contact and the decrease of internal quantum efticiency of multiple quantum well (MQW), respectively. 相似文献
50.
The light extraction efficiencies have been calculated for various InGaN/GaN multiple quantum well nanostructure light-emitting diodes including nanopillar,nanorough of P-GaN surface,coreshell and nano-interlayer structure.From the calculated results we can see that the light extraction efficiency is remarkably improved in the nanostructures,especially those with an InGaN or AlGaN nano-interlayer.With a 420-nm luminescence wavelength,the light extraction efficiency can reach as high as 65% for the InGaN or AlGaN nano-interlayer structure with appropriate In or Al content while only 26% for the planar structure. 相似文献