In_（0．6）Ga_（0．4）As／InP应变量子阱的光致发光

本文研究了不同阱宽的Ｉｎ０．６Ｇａ０．４Ａｓ／ＩｎＰ应变量子阱的光致发光，通过量子尺寸效应和压缩应变引起的峰值能量位移判断了不同谱峰的跃迁．在一定的温度范围内，相应量子阱的发光强度随着温度的升高而增加，当温度高出此范围，其光强随温度的升高而减小，此温区不仅与阱宽有关。且随激发光强而变化．我们用量子阱的限制效应和激子的转换机理，初步探讨了此温度范围的形成和消失．     

俄歇复合对应变量子阱激光器阈值电流的影响

通过考虑不同因素对压应变和张应变量子阱激光器阈值电流和特征温度的影响，得到了俄歇复合和非俄歇复合对阈值电流起主要作用的转变温度Tc，小于Tc时，主要是非俄歇复合；大于Tc时，主要是俄歇复合，而且张应变量子阱激光器转变温度要比压应变量子阱激光器的转变温度要高；张应变量子阱激光器与压应变量子阱激光器相比，阈值电流更低，特征温度更高。     

InGaN蓝光LED量子效率与注入电流的关系研究

研究了InGaN蓝光LED量子效率随注入电流的变化关系,当注入电流还未达到额定电流时,LED量子效率就随着注入电流增加而快速降低。通过Matlab计算出在俄歇复合的无辐射复合机制下量子效率与注入电流的理论关系式。与实验值的拟合结果显示,大电流注入下,LED的效率衰落同时由俄歇复合及其产生的热电子从发光有源区泄露引起。由蓝光LED这一效率-电流特性,提出了增强InGaN蓝光LED效率的途径。     

俄歇复合对InGaAsP量子阱激光器的阈值电流的影响

为了改善InGaAsP激光器阈值电流与温度的关系,人们寄希望于量子阱(QW)结构。虽然分析了GaAs量子辐激光器的辐射电流与温度的关系,但不能用于InGaAsP量子阱激光器,因为俄歇效应对这种激光器有着重要的作用。本文分析了量子的尺寸对俄歇电流的影响,揭示出了InGaAsP量子阱激光器的低阈值电流和高特征温度T_0的极限值。计算了量子阱结构中导带和价带次能带之间一切可能跃迁的增益、辐射和俄歇系数。它们的全量子化状态到体状态跃迁范围的性质已经搞清楚。在载流子间无相互作用条件下,采用K-选择准则,InGaAsP和GaAs量子阱激光器的阈值电流计算值与文     

0.1电子伏碲镉汞光导探测器的性能

0.1电子伏HgCdTe光导器件的研制进展使D~*和响应率的性能在宽的温度范围内接近由俄歇复合理论预测的理论热极限,同时显著地改善了1/f噪声、阵列的均匀性和烘烤稳定性。简单的俄歇理论亦说明了70 K以上所测得的产生复合噪声随温度的变化。     

InGaAsP量子阱激光器结构与阈值电流密度的关系

计入俄歇复合过程的影响,从理论上研究了InGaAsP多量子阱激光器的阈值电流密度。在评述辐射和俄歇过程中考虑了二维载流子在量子化次能带间的所有可能跃迁。俄歇复合电流强烈地依赖于量子阱结构,这样就需要对量子阱激光器的结构进行精心的设计。此外,还阐述了能获得最低阈值电流密度的InGaAsP多量子阱激光器的结构设计程序。     

观测InGaAsP激光器的俄歇复合及载流子泄漏

俄歇复合和载流子泄漏已作为InGaAsP激光器和LED_s的温度灵敏性高和内量子效率低的原因而被提出。本文发表了通过测量载流子寿命和自发辐射率而获得辐射和俄歇复合率以及泄漏电流。发现俄歇复合率和泄漏电流强烈地依赖于掺杂程度。使用的器件是1.3μm InGaAsP双异质结激光器,其氧化物隔离接触条100μm,有源     

温度和材料参数对InAsxSb1-x俄歇复合寿命影响的数值分析

工作在中长波的红外探测器可被广泛应用在空间成像、军事和通信等领域,锑基InAsSb材料由于其特殊的性质是制作长波非致冷光子探测器的理想材料。俄歇复合寿命是影响探测器性能的重要因素之一,文章采用Matlab软件模拟研究了n型和p型InAsxSb1-x材料的俄歇复合寿命随温度、As组分及载流子浓度的变化。对确定的As组分,可通过优化工作温度及载流子浓度获得较长的俄歇复合寿命。当载流子浓度为3.2×1015 cm-3、温度为200K时,n型InAs0.35Sb0.65的俄歇复合寿命最大为2.91×10-9 s。     

两段式双稳半导体激光器下跳阈值点的确定

对Ｋｕｚｎｅｔｓｏｖ采用的速率方程加以修正，考虑了俄歇效应的影响，我们流子寿命不再作为常数处理，而写成载流子浓度的函数。由此导出了两段式双稳半导体激光器下跳阈值点载流子浓度所满足的隐函数解析表达式。通过该解析表达式确定出了器件存在双稳的必要条件。进而讨论了俄歇复合系数、吸收区偏置电流和长度等对双稳特性的影响。     

自组织生长InAs量子点发光的温度特性

本文报道ＩｎＡｓ／ＧａＡｓ自组织生长量子点结构中发光的温度特性．在１２～１５０Ｋ温度范围内，实验测得的ＩｎＡｓ激子发光能量随温度增加明显红移，其红移速率远大于ＩｎＡｓ带隙的温度关系，而光谱宽度则明显减小．这些结果表明ＩｎＡｓ量子点结构是一种强耦合系统，局域在ＩｎＡｓ量子点中的载流子波函数会相互交途、相互贯穿，从而增强了载流子的弛豫过程．     

Localized Auger Recombination in Quantum-Dot Lasers

We have calculated radiative and Auger recombination rates due to localized recombination in individual dots, for an ensemble of 10⁶ dots with carriers occupying the inhomogeneous distribution of energy states according to global Fermi-Dirac statistics. The recombination rates cannot be represented by simple power laws, though the Auger rate has a stronger dependence on the ensemble electron population than radiative recombination. Using single-dot recombination probabilities which are independent of temperature, the ensemble recombination rates and modal gain decrease with increasing temperature at fixed population. The net effect is that the threshold current density increases with increasing temperature due to the increase in threshold carrier density. The most significant consequence of these effects is that the temperature dependence of the Auger recombination rate at threshold is much weaker than in quantum wells, being characterized by a T₀ value of about 325 K. Observations of a strong temperature dependence of threshold in quantum dot lasers may have explanations other than Auger recombination, such as recombination from higher lying states, or carrier leakage.     

Evidence of the importance of Auger recombination for InGaAsP lasers

The temperature dependence of Auger recombination in InGaAsP can be described by two regions, one with a slow increase of the Auger coefficient and one with a strong increase. This behaviour is similar to that of the threshold current of an InGaAsP laser. In particular, the slope of the temperature curve of the Auger coefficient changes at T = 255 K, which is exactly the break point temperature of the threshold current. Auger recombination therefore seems to be the most important cause for the temperature dependence of the threshold current in InGaAsP lasers.     

Evidence for large monomolecular recombination contribution tothreshold current in 1.3 μm GaInNAs semiconductor lasers

The spontaneous emission, L, through a window in the substrate electrode of 1.3 μm GaInNAs MQW lasers was studied as a function of current, I, and temperature, T Close to room temperature, a characteristic temperature at threshold T,(L) T was observed as expected for band-to-band recombination in ideal quantum well devices. However, T ₀(I_th)≃T/3 indicating other processes occur. Analysis of the variation of L with I, reveals that monomolecular recombination contributes more than 50% to the total current at threshold and also that some Auger recombination may be present     

Analysis and simulation of a mid-infrared P/sup +/-InAs/sub 0.55/Sb/sub 0.15/P/sub 0.30//n/sup 0/-InAs/sub 0.89/Sb/sub 0.11//N/sup +/-InAs/sub 0.55/Sb/sub 0.15/P/sub 0.30/ double heterojunction photodetector grown by LPE

A photovoltaic detector based on an N/sup +/-InAs/sub 0.55/Sb/sub 0.15/P/sub 0.30//n/sup 0/-InAs/sub 0.89/Sb/sub 0./$ d1/sub 1//P/sup +/-InAs/sub 0.55/Sb/sub 0.15/P/sub 0.30/ double heterostructure (DH) suitable for operation in the mid-infrared (MIR) spectral region (2 to 5 /spl mu/m) at room temperature has been studied. A physics based closed form model of the device has been developed to investigate the relative importance of the different mechanisms which determine dark current and photoresponse. The results obtained on the basis of the model have been compared and contrasted with those obtained from experimental measurements on DH detectors fabricated previously in our laboratory using liquid phase epitaxy (LPE). The model helps to explain the various physical mechanisms that shape the characteristics of the device under room temperature operation. It can also be used to optimize the performance of the photodetector in respect of dark current, responsivity and detectivity. A comparison of theoretical predictions and experimental results revealed that Shockley-Read-Hall (SRH) recombination is more important than Auger recombination in determining the room temperature detector performance when the concentration of nonradiative recombination centers in our material exceeds 10/sup 17/ cm/sup -3/. Furthermore, compositional grading in the cladding regions of the double heterostructure has been found to be responsible for the reduction of the detectivity of the device in the shorter wavelength region.     

Temperature dependence of the threshold current of QW lasers

The temperature dependence of the threshold current in GaInAs-based laser structures has been studied in a wide temperature range (4.2 ≤ T ≤ 290 K). It is shown that this dependence is monotonic in the entire temperature interval studied. Theoretical expressions for the threshold carrier density are derived and it is demonstrated that this density depends on temperature linearly. It is shown that the main contribution to the threshold current comes from monomolecular (Shockley-Read) recombination at low temperatures. At T > 77 K, the threshold current is determined by radiative recombination. At higher temperatures, close to room temperature, Auger recombination also makes a contribution. The threshold current grows with temperature linearly in the case of radiative recombination and in accordance with T ³ in the case of Auger recombination.     

Influence of temperature on Auger recombination lifetime in In1?xGaxAs materials

The influence of temperature and Ga composition on Auger recombination lifetime in n-type and p-type In1-xGaxAs materials is investigated through the simulation, assuming the concentrations of electrons and holes are 1017 cm-3 and 1018 cm-3, respectively. The results show that the temperature has little influence on Auger recombination lifetime of In1-xGaxAs materials at x<0.3. However, it has a great impact when x>0.3 and the effect is more obvious at a lower temperature. Moreover, Auger ...     

Theory of the temperature dependence of the threshold current of an InGaAsP laser

The threshold current of an InGaAsP laser is calculated, where the radiative emission, reflection and absorption losses, and Auger recombination are considered. Moreover, the enhancement of the threshold carrier density at high temperatures is an important point. A mechanism for this enhancement is discussed. Then we obtain an excellent agreement with the measured temperature dependence of the threshold current, in particular the To-values for T≷TBand the break point TB. The reason for this break point is that the radiative recombination dominates for T < TB, whereas the strongly temperature dependent valence band Auger process becomes more and more important for T > TB. It is this process which causes the strong increase of the threshold current in the room temperature range.     

Dynamics of photoluminescence and recombination processes in Sb-containing laser nanostructures

The dynamics of interband photoluminescence has been studied at various temperatures and excitation levels in structures with quantum wells based on InGaAsSb alloys and barriers based on AlGaAsSb and AlInGaAsSb alloys. The lifetimes of optically injected charge carriers in quantum wells at various temperatures and levels of optical excitation have been experimentally determined. An increase in the recombination rate in structures with deeper InGaAsSb/AlGaAsSb quantum wells for electrons is attributed to manifestation of resonant Auger recombination. The Auger recombination brings about heating of electrons and holes in lower subbands of dimensional quantization. The temperature of charge carriers in the course of Auger recombination is estimated using the equation for balance of power with accumulation of nonequilibrium optical phonons taken into account. The studied structures were used to fabricate lasers of two types with lasing wavelength of approximately 3 μm; it is shown that the use of a quinary alloy as the material for the barrier leads to an improvement in the characteristics of the lasers.     

The performance of double active region InGaAsP lasers

The light-current characteristic and temperature behavior of the double-carrier-confinement (DCC) InGaAsP laser are shown to be largely determined by Auger recombination. The carrier distributions in the two active regions, especially their relative fractions, play a major role in device behavior. A self-consistent, comprehensive numerical laser model is used to analyze a set of devices showing that superlinearity and possibly bistability are due to saturable absorption in the second active region and that a high characteristic temperature is usually tied with a higher threshold current density because of substantial Auger recombination rates in this type of device