共查询到19条相似文献,搜索用时 140 毫秒
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用深能级瞬态谱(DLTS)技术测量了高温退火的Be和Si共注入的LEC半绝缘GaAs(无掺杂)。在多子脉冲作用下的Al/Be-Si共注LECSIGaAs肖特基势垒中,观测到E01(0.298),E02(0.341),E03(0.555)和E04(0.821)等四个电子陷阱以及两个主要的少子(空穴)陷阱H'03(0.54)和H″03(0.57)。两少子陷阱的DLTS信号具有若干特点,比如它们的DLTS·峰难于通过增宽脉冲达到最大高度;以及峰的高度强烈地依赖于温度等。这些现象可以用少子陷阱的少子俘获和热发射理论进行合理地解释。鉴于用DLTS技术测量这种陷阱的困难,我们用恒温电容瞬态技术测定它们的空穴表观激活能分别为0.54和0.57eV。它们是新观测到的和Be-Si共注SIGaAs有关缺陷。
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应用深能级瞬态谱(DLTs)技术详细研究低压-金属有机物汽相外延(LP-MOVPE)生长的Ga_(0.47)In_(0.53)As/Inp量子阱、宽接触和质子轰击条形异质结激光器中的深能级。样品的DLTS表明,在宽接触激光器的i-Ga_(0.47)In_(0.53)As有源层里观察到H1(E_v+0.09eV)和E1(E_c-0.35eV)陷阱,它们可能分别与样品生长过程中扩散到i-Ga_(0.47)In_(0.53)As有源层的Zn和材料本身的原生缺陷有关。而条形激光器的i-Ga_(0.47)In_(0.53)As有源层的H2(E_v+0.11eV)和E2(E_v-0.42eV)陷阱则可能是H1和E1与质子轰击引起的损伤相互作用的产物。 相似文献
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采用定电容电压法,测量了n型Al0.26Ga0.74As:Sn中DX中心电子热俘获瞬态,以及不同俘获时间后的电子热发射瞬态;并对瞬态数据进行数值Laplace变换,得到其Laplace缺陷谱(LDS)。通过分析LDS谱,确定了电子热俘获和热发射LDS谱之间的对应关系,从而得到热俘获系数对温度依赖关系,以及与Sn相关的DX中心部分电子热俘获势垒的精细结构;通过第一原理赝势法计算表明,Sn附近的Al/Ga原子的不同配置是电子热俘获势垒精细结构产生的主要原因。 相似文献
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采用定电容电压法,测量了n型Al026Ga074As∶Sn中DX中心电子热俘获瞬态,以及不同俘获时间后的电子热发射瞬态;并对瞬态数据进行数值Laplace变换,得到其Laplace缺陷谱(LDS).通过分析LDS谱,确定了电子热俘获和热发射LDS谱之间的对应关系,从而得到热俘获系数对温度依赖关系,以及与Sn相关的DX中心部分电子热俘获势垒的精细结构;通过第一原理赝势法计算表明,Sn附近的AlGa原子的不同配置是电子热俘获势垒精细结构产生的主要原因 相似文献
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纳米SiC蓝光发射的研究 总被引:4,自引:0,他引:4
在4.68eV的激光激发下,室温CVD合成的纳米SiC粉体,可发射475nm的蓝光,经600~1100℃在N2气氛下进行快速退火(RTA)处理,其荧光强度随退火温度升高而增强,当T≥900℃时,荧光强度下降,但发光峰位与退火温度无关.通过XRD、IR、TEM、XPS等研究,认为纳米SiC中与氧有关的缺陷可能是引起475nm蓝光发射的主要原因 相似文献
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J.S. Kim E.K. Kim K. Park E. Yoon I.K. Han Y.J. Park 《Physica E: Low-dimensional Systems and Nanostructures》2005,26(1-4):91
We have studied the effects of thermal annealing on the electrical properties of InAs/InP self-assembled quantum dots (QDs) using deep level transient spectroscopy (DLTS). It was found from the DLTS measurements that the activation energy of the QD signal varied from 0.47 to 0.60 eV and the emission cross section changed from 1.01×10−15 to 9.63×10−14 cm2 when the annealing temperature increased up to 700 °C. As a result of the thermal annealing process at the temperature ranging from 500 to 600 °C, the higher activation energy and the larger emission cross section of the QD related signal were observed for the annealed samples compared to those for the as-grown sample. On the basis of the capture barrier height for the QDs structure being lowered from 0.24 to 0.06 eV at the annealing temperature of 700 °C, thermal damage was considered as the reason. The appropriate annealing process can provide a clue for the engineering of the energy levels in the self-assembled QD structures. 相似文献
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DX center has been characterized in four GaAs---AlAs superlattices grown by MBE at 580°C. The structures are uniformly Si-doped or selectively Si-doped in the AlAs layers or in the middle of the GaAs layers or on both sides of the interfaces. Deep level transient spectroscopy measurements (DLTS) put in evidence one dominant electron trap, with an activation energy for thermal emission of about 0.42eV for all the superlattices. This defect shows a thermally activated capture cross section and a large concentration except for the case where the only GaAs layers are doped. For the first time, a study of the capture reveals a capture activation energy of 0.36-0.37 eV, which allows us to locate the DX level nearly 60 meV below the conduction miniband. From these results, we show that the observed DX center is related to silicon in the AlAs layers. For the case when the AlAs barriers are not doped, the DX level is due to the Si diffusion from the middle of the wells towards the barriers, the Si atoms having diffused during the growth. 相似文献
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F.D. Auret P.J. Janse van Rensburg W.E. Meyer S.M.M. Coelho Vl. Kolkovsky J.R. Botha C. Nyamhere A. Venter 《Physica B: Condensed Matter》2012,407(10):1497-1500
The electronic properties of defects introduced by low energy inductively coupled Ar plasma etching of n-type (Si doped) GaAs were investigated by deep level transient spectroscopy (DLTS) and Laplace DLTS. Several prominent electron traps (Ec—0.046 eV, Ec—0.186 eV, Ec—0.314 eV. Ec—0.528 eV and Ec—0.605 eV) were detected. The metastable defect Ec—0.046 eV having a trap signature similar to E1 is observed for the first time. Ec—0.314 eV and Ec—0.605 eV are metastable and appear to be similar to the M3 and M4 defects present in dc H-plasma exposed GaAs. 相似文献
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《中国物理 B》2020,(1)
Low temperature(77 K)photoluminescence measurements have been performed on different GaAs substrates to evaluate the GaAs crystal quality.Several defect-related luminescence peaks have been observed,including 1.452 eV,1.476 eV,1.326 eV peaks deriving from 78 meV Ga_(As) antisite defects,and 1.372 eV,1.289 eV peaks resulting from As vacancy related defects.Changes in photoluminescence emission intensity and emission energy as a function of temperature and excitation power lead to the identification of the defect states.The luminescence mechanisms of the defect states were studied by photoluminescence spectroscopy and the growth quality of GaAs crystal was evaluated. 相似文献
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利用深能级瞬态谱(DLTS)研究了气源分子束外延(GSMBE)生长的InP1-xBix材料中深能级中心的性质。在未有意掺杂的InP中测量到一个多数载流子深能级中心E1,E1的能级位置为Ec-0.38 e V,俘获截面为1.87×10~(-15)cm~2。在未有意掺杂的InP0.9751Bi0.0249中测量到一个少数载流子深能级中心H1,H1的能级位置为Ev+0.31 eV,俘获截面为2.87×10~(-17)cm~2。深中心E1应该起源于本征反位缺陷PIn,深中心H1可能来源于形成的Bi原子对或者更复杂的与Bi相关的团簇。明确这些缺陷的起源对于InPBi材料在器件应用方面具有重要的意义。 相似文献
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Boussairi Bouzazi Hidetoshi SuzukiNobuaki Kojima Yoshio OhshitaMasafumi Yamaguchi 《Physica B: Condensed Matter》2011,406(5):1070-1075
A nitrogen-related electron trap (E1), located approximately 0.33 eV from the conduction band minimum of GaAsN grown by chemical beam epitaxy, was confirmed by investigating the dependence of its density with N concentration. This level exhibits a high capture cross section compared with that of native defects in GaAs. Its density increases significantly with N concentration, persists following post-thermal annealing, and was found to be quasi-uniformly distributed. These results indicate that E1 is a stable defect that is formed during growth to compensate for the tensile strain caused by N. Furthermore, E1 was confirmed to act as a recombination center by comparing its activation energy with that of the recombination current in the depletion region of the alloy. However, this technique cannot characterize the electron−hole (e-h) recombination process. For that, double carrier pulse deep level transient spectroscopy is used to confirm the non-radiative e-h recombination process through E1, to estimate the capture cross section of holes, and to evaluate the energy of multi-phonon emission. Furthermore, a configuration coordinate diagram is modeled based on the physical parameters of E1. 相似文献
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用DLTS和单次脉冲瞬态电容技术研究了液相外延生长的双异质结AlxGa1-xAs/GaAs发光管,掺Si的n-Al0.05Ga0.95As有源层中的深能级。着重分析了一个与氧有关的电子陷阱,其发射激活能为EC-ED=0.29eV。我们发现该电子陷阱随正向注入脉冲宽度tp的增加DLTS峰向低温移动,即在确定的温度下发射率随tp的增加而增加。用DLTS首次测得该能级的俘获瞬态谱,发现俘获峰随反向撤空脉冲宽度tR的增加向低温端移动,即在确定的温度下俘获率随tR的增加而增加,并且俘获激活能从△Eσ=0.28eV变化到0.26eV,用位形坐标图讨论了引起变化的原因。 相似文献
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F.D. Auret S.M.M. Coelho G. Myburg P.J. Janse van Rensburg W.E. Meyer 《Physica B: Condensed Matter》2009,404(22):4376-4378
Low energy (±80 eV) Ar plasma etching has been successfully used to etch several semiconductors, including GaAs, GaP, and InP. We have studied the only prominent defect, E0.31, introduced in n-type Sb-doped Ge during this process by deep level transient spectroscopy (DLTS). The E0.31 defect has an energy level at 0.31 eV below the conduction band and an apparent capture cross-section of 1.4×10−14 cm2. The fact that no V-Sb defects and no interstitial-related defects were observed implies that the etch process did not introduce single vacancies or single interstitials. Instead it appears that higher order vacancy or interstitial clusters are introduced due to the large amount of energy deposited per unit length along the path of the Ar ions in the Ge. The E0.31 defect may therefore be related to one of these defects. DLTS depth profiling revealed the E0.31 concentration had a maximum (6×1013 cm−3) close to the Ge surface and then it decreased more or less exponentially into the Ge. Finally, annealing at 250 °C reduced the E0.31 concentration to below the DLTS detection limit. 相似文献
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The electric field enhanced thermal emission rate was measured for the Ec -0.35 eV level of GaAs using a new reverse-bias pulsed DLTS technique. It is shown that the observed field and its temperature dependencies are probably the result of the Poole-Frenkel emission from a polarization potential well. From this study and with other annealing and the capture cross-section data, it is concluded that the defect is probably of a neutral-impurity type. 相似文献