共查询到20条相似文献,搜索用时 46 毫秒
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用光调制吸收光谱方法在不同压力条件下研究了In_(0.15)Ga_(0.85)As/GaAs应变多量子阱的子能带跃迁,发现子能带跃迁能量随压力的变化行为与构成量子阱的组成体材料带间跃迁能量的变化相似,并且子能带跃迁能量压力系数与量子阱的宽度有关。还讨论了压力可能引起的导带不连续率的变化和In_(0.15) Ga_(0.85)As应变层的临界厚度。 相似文献
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AlAs/GaAs/In0.1Ga0.9As/GaAs/AlAs double-barrier resonant tunneling diodes(DBRTDs) grown on a semi-insulated GaAs substrate with molecular beam epitaxy is demonstrated.By sandwiching the In0.1Ga0.9As layer between GaAs layers,potential wells beside the two sides of barrier are deepened,resulting in an increase of the peak-to-valley current ratio (PVCR) and a peak current density.A special shape of collector is designed in order to reduce contact resistance and non-uniformity of the current;as a result the total current density in the device is increased.The use of thin barriers is also helpful for the improvement of the PVCR and the peak current density in DBRTDs.The devices exhibit a maximum PVCR of 13.98 and a peak current density of 89kA/cm2 at room temperature. 相似文献
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We have investigated a SiO_2/SiN_x/SiO_2 composite insulation layer structured gate dielectric for an organic thin film transistor(OTFT) with the purpose of improving the performance of the SiO_2 gate insulator. The SiO_2/SiN_x/SiO_2 composite insulation layer was prepared by magnetron sputtering.Compared with the same thickness of a SiO_2 insulation layer device,the SiO_2/SiN_x/SiO_2 composite insulation layer is an effective method of fabricating OTFT with improved electric characteristics and decrease... 相似文献
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介绍了一种新型长波长InP基一镜斜置三镜腔型(OMITMiC)光电探测器,并对其进行了数值模拟。介绍了该光电探测器的两项关键制备工艺。首先,利用动态掩膜湿法腐蚀技术,通过调节HCl:HF:CrO3腐蚀溶液的选择比。在与InP晶格匹配的In0.72Ga0.28As0.6P0.4外延层上制备出了不同倾角的楔形结构。其次,利用选择性湿法腐蚀技术,通过FeCl3;H2O溶液对In0.53Ga0.47As牺牲层的腐蚀,制备出了具有InP/空气隙的高反射率分布式布拉格反射镜(DBR)。 相似文献
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The dark current of In_(0.47) Ga_(0.53) As/InP heterojunction photodiodes (HPDs) was analysed. We found that there exists a new dark current component-deep level-assisted tunnelling current.DLTS was used to measure the In_(0.47)Ga_(0.53)As/InP HPDs. An electronic trap which has a thermal activation energy of O.44 eV, level concentration of 3.10×10^(13)cm^(-3) and electronic capture cross section of 1.72×10^(12)cm^2 has been found.It s existence results in the new tunnelling current. 相似文献
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在77K,0—60kbar范围内对在同一衬底上生长的In_(0.15)Ga_(0.85)As/GaAs和GaAs/Al_(0.3)Ga_(0.7)As量子阱的静压下的光致发光进行了对照研究。在GaAs/Al_(0.3)Ga_(0.7)As量子阱中同时观察到导带到轻重空穴子带的跃迁。而在In_(0.15)Ga_(0.85)As/GaAs阱中只观察到导带到重空穴子带的跃迁。与GaAs/Al_(0.3)Ga_(0.7)As的情况相反,In_(0.15)Ga_(0.85)As/GaAs 量子阱的光致发光峰的压力系数随阱宽的减小而增加。在压力大于48kbar时观察到多个与间接跃迁有关的发光峰,对此进行了简短的讨论。 相似文献
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应用电子束直写技术成功制作了栅长0.15μm的高性能In0.52Al0.48As/In0.53Ga0.47As GaAs MHEMT。从工艺角度,结合器件的小信号等效电路的理论分析,优化了器件源漏间距,从而减小了器件寄生参数,达到了较好的器件性能。最终制作的In0.52Al0.48As/In0.53Ga0.47As MHEMT饱和电流达到495mA/mm,夹断电压-0.8V,在Vgs为-0.19V时的最大非本征跨导gm为1032mS/mm,截止频率ft达到156GHz,最大振荡频率fmax大于150GHz。 相似文献
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用光荧光谱和原子力显微镜测试技术系统研究了在2 nm In0.2Ga0.8As和x ML GaAs的复合应力缓冲层上生长的InAs/GaAs自组织量子点的发光特性和表面形貌.采用In0.2Ga0.8As与薄层GaAs复合的应力缓冲层,由于减少了晶格失配度致使量子点密度从约1.7×109 cm-2显著增加到约3.8×109cm-2.同时,复合层也有利于提高量子点中In的组份,使量子点的高宽比增加,促进量子点发光峰红移.对于x=10 ML的样品室温下基态发光峰达到1350 nm. 相似文献
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The influence of capping layer composition was examined in accelerated stress-migration performance of AlCu(0.5%) narrow stripe lines. Using resistance monitoring and Scanning Electron Microscopy, we determined that metallisation with bilayer Ti/TiN ARC top layer induced more stress voiding than metallisation with single TiN ARC layer. These experimental results are discussed on the basis of a void growth mechanism provided by diffusion at the interface between AlCu and ARC top layer. 相似文献
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采用闭管扩散方式实现了Zn元素在晶格匹配InP/In_(0.53)Ga_(0.47)As及晶格失配InP/In_(0.82)Ga_(0.18)AS两种异质结构材料中的P型掺杂,利用二次离子质谱(SIMS)以及扫描电容显微技术(SCM)对Zn在两种材料中的扩散机制进行了研究.SIMS测试表明:Zn元素在晶格失配材料中的扩散速度远大于在晶格匹配材料中的扩散速度,而SCM测试表明:两种材料中的实际PN结深度与SIMS测得的Zn扩散深度之间存在一定的差值,这是由于扩散进入材料中的Zn元素并没有被完全激活,而晶格失配材料中Zn的激活效率相对更低,使得晶格失配材料中Zn元素扩散深度与PN结深度的差值更大.SCM法是一种新颖快捷的半导体结深测试法,对于半导体器件工艺研究具有重要的指导意义. 相似文献
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Hui Hao Xiao Chen Zhengcheng Li Yang Shen Hu Wang Yanfei Zhao Rong Huang Tong Liu Jian Liang Yuxin An Qing Peng Sunan Ding 《半导体学报》2019,40(1):91-97
High quality gallium oxide(Ga_2O_3) thin films are deposited by remote plasma-enhanced atomic layer deposition(RPEALD) with trimethylgallium(TMG) and oxygen plasma as precursors. By introducing in-situ NH3 plasma pretreatment on the substrates, the deposition rate of Ga_2O_3 films on Si and GaN are remarkably enhanced, reached to 0.53 and 0.46 ?/cycle at 250 °C,respectively. The increasing of deposition rate is attributed to more hydroxyls(–OH) generated on the substrate surfaces after NH3 pretreatment, which has no effect on the stoichiometry and surface morphology of the oxide films, but only modifies the surface states of substrates by enhancing reactive site density. Ga_2O_3 film deposited on GaN wafer is crystallized at 250 °C, with an epitaxial interface between Ga_2O_3 and GaN clearly observed. This is potentially very important for reducing the interface state density through high quality passivation. 相似文献
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用固态分子束外延技术生长了高应变In0.45Ga0.55As/GaAs量子阱材料. 研究了快速热退火对高应变InGaAs/GaAs量子阱材料光学性质的影响. 本文采用假设InGaAs/GaAs量子阱中的In-Ga原子扩散为误差函数扩散并解任意形状量子阱的薛定谔方程的方法,对不同退火温度下InGaAs/GaAs量子阱室温光致发光峰值波长拟合,得到了In原子在高应变InGaAs/GaAs量子阱中的扩散系数以及扩散激活能(0.88eV) . 相似文献
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In this paper, we present the performance of optical coating systems coupled with AlGaAs window layers over GaAs solar cells. Single, double, and triple antireflecting coatings and window layers with constant and graded aluminum content are considered. Comparison between constant and graded window layers is established. To better represent reality, practical factors such as absorption of materials even for antireflecting coatings and the oxidation at window layer surface due to its high aluminum content are also included in the calculations. The design criteria to determine the optimum thickness of each layer is the achievement of maximum photogenerated current density. For this purpose and to account for terrestrial concentrator GaAs solar cells, the inclusion of direct terrestrial solar spectrum together with the internal spectral response of the device are taken into account. Finally, the best antireflecting coating/AlGaAs window layer couplings for different cases are presented 相似文献
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选取厚度为5、10和20nm的TiO2薄膜为过渡层,采用sol-gel法在Pt/Ti/SiO2/Si衬底上制备了Bi3.54Nd0.46Ti3O12(BNT)铁电薄膜,研究了过渡层厚度对铁电薄膜微观结构及电学性质的影响。结果表明,加入TiO2过渡层后,BNT薄膜微观结构得到改善,εr及2Pr值大幅提高,介电损耗及漏电流密度都有降低。过渡层厚度为20nm时,BNT薄膜的εr、tanδ及2Pr值分别为325、0.025(测试频率为10kHz)和36.1×10–6C/cm2,漏电流密度为8.45×10–7A/cm2(外加电场为100×103V/cm)。 相似文献
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设计良好的减反膜系,提高太阳电池的光电转换效率是太阳电池研制中的一个重要问题.文章从减反膜理论出发,利用计算机软件模拟分析,获得了单层膜、双层膜系反射率百分比与波长的关系,并给出了具体入射波长(即632.8 nm、800 nm)条件下膜的最佳厚度.采用PC1D软件模拟了覆盖减反膜的单晶硅电池的I-V曲线,证实电池转换效率大大提高.研究结果可应用于太阳电池的设计中. 相似文献
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利用传输矩阵法对不同入射介质的GaN基分布布拉格反射器(DBR)进行了反射谱的理论分析。计算表明,入射介质的折射率与低周期DBR反射率呈二次函数关系,与高周期DBR反射率近似线性关系。根据这些特点,推导出估算DBR在LED器件中的实际反射率公式。分析了从空气和Al_(0.4)Ga_(0.5)In_(0.1)N入射介质下不同GaN基DBR结构的反射光谱差异。为减弱入射介质对DBR反射谱的影响以及改善材料结构的质量,设计了半混合GaN基DBR结构。分析指出,半混合DBR在材料结构生长和光谱方面比传统DBR更有优势。 相似文献