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1.
本文报道了空间差分光调制反射光谱,指出了它与常规光调制反射谱的区别,与常规光调制反射光谱相比较,它具有更好的信噪比和灵敏度。利用该光谱方法对GaAs/AlGaAs量子阱的实验测量结果表明,空间差分光调制反射光谱具有丰富的光谱结构。 相似文献
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本文首次报道了异质结NIPI结构的室温光调制反射光谱及其随调制光强的变化,并对调制机制进行了讨论.最后,通过比较理论与实验结果,对所观测到的跃迁过程进行了指派. 相似文献
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本文讨论了量子阱的光调制反射谱(PR)线形,并采用光调制反射谱研究了MBE GaAs_(1-x)Sb_x/GaAs异质结、应变层量子阱。可见,用PR谱研究MBE外延膜具有一定的优越性。 相似文献
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提出一种微接触电调制反射谱(LCER)测试方法,该方示与无接触电调制反射(CER)谱相比较,可极大降低调制电压。给出了自制的详细样品架结构,测量了InGaAs/GaAs量子阱样品,并与光调制反射谱(PR)相比较,结果证实了此方法的可行性和高光谱灵敏度,表明样品与电极的轻微接触既对测量结果没有明显的影响,又可简化测试条件,降低对测量环境的要求,是研究半导体材料和微结构一种方便而又有效的方法。 相似文献
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对In(0.2)Ga(0.8)As/GaAs应变多量子阱在77K下的光调制反射谱(PR)和热调制反射谱(TR)进行了实验研究.对PR结果的线形拟合指认了应变多量子阱中子能级的跃迁,并与理论计算结果作了比较.实验对比确认PR中11H、13H等跃迁结构为非耦合态、具有电场调制机构的一阶微商性质.而11L、31H、22H等跃迁结构为阶间耦合态,对这些隧穿耦合的低场调制产生三阶微商特性. 相似文献
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研究了GaInNAs/GaAs多量子阱在不同温度和激发功率下的光致发光(PL)谱以及光调制反射(PR)谱.发现PL谱主发光峰的能量位置随温度的变化不满足Varshni关系,而是呈现出反常的S型温度依赖关系.进一步测量,特别是在较低的激发光功率密度下,发现有两个不同来源的发光峰,它们分别对应于氮引起的杂质束缚态和带间的激子复合发光.随温度变化,这两个发光峰相对强度发生变化,造成主峰(最强的峰)的位置发生切换,从而导致表观上的S型温度依赖关系.采用一个基于载流子热激发和出空过程的模型来解释氮杂质团簇引起的束缚态发光峰的温度依赖关系. 相似文献
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研究了GaInNAs/GaAs多量子阱在不同温度和激发功率下的光致发光(PL)谱以及光调制反射(PR)谱.发现PL谱主发光峰的能量位置随温度的变化不满足Varshni关系,而是呈现出反常的S型温度依赖关系.进一步测量,特别是在较低的激发光功率密度下,发现有两个不同来源的发光峰,它们分别对应于氮引起的杂质束缚态和带间的激子复合发光.随温度变化,这两个发光峰相对强度发生变化,造成主峰(最强的峰)的位置发生切换,从而导致表观上的S型温度依赖关系.采用一个基于载流子热激发和出空过程的模型来解释氮杂质团簇引起的束缚态发光峰的温度依赖关系. 相似文献
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Jan Vaniš Ji?í Zelinka Mohamed Henini Karel Melichar Filip Šroubek 《Microelectronics Journal》2009,40(3):496-498
Self-assembled InAs quantum dots (SAQDs) in GaAs/GaAlAs structures grown by molecular beam epitaxy (MBE) and metal-organic vapour phase epitaxy (MOVPE) of similar size was examined by ballistic electron emission spectroscopy. Ballistic current-voltage characteristics through the QD in the voltage range from 0.55 to 0.9 V (range where the presence of resonance states of QD is expected) with its derivative (the derivation of the spectroscopic characteristics represents quantum levels in the QD) are given. Differences in the intensities and sharpnesses of the QD levels for MBE and MOVPE grown QDs are observed. 相似文献
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B.D. Barkana 《Microelectronics Journal》2008,39(12):1504-1508
Electrical properties of a resonant-tunneling-semiconductor-controlled rectifier (RT-SCR) model have been presented. The current, temperature, gain, doping concentration, and layer size versus voltage relationships have been numerically obtained. The RT-SCR device requires smaller turn-on voltage than a comparable traditional device for the same gate current. This indicates that, in comparison with the traditional thyristor, a smaller control current may be used to turn on the device at a particular voltage. Characteristics of the device are affected by p1, n1, and p2 regions. It is showed that higher doping concentrations cause lower turn-on voltages and an increase in the region width results in higher turn-on voltages for p1 and p2 regions. Changing the doping concentration and width in n1 region affects the characteristics of the structure differently from that of the p1 and p2 regions. 相似文献
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《Electron Device Letters, IEEE》1982,3(8):194-196
The advantages of the modulation-doped heterostructure over conventional materials structures for high speed CCD applications are outlined. In addition, the first demonstration of charge transfer in a modulation-doped AlGaAs/GaAs heterojunction is reported. A ten cell, three phase Schottky barrier gate CCD was fabricated using this structure and operated as a shift register. The details of the device fabrication and characterization are presented. 相似文献
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A theoretical model has been developed to study nonlinear behaviors in a GaAs/AlGaAs heterostructure.We show that the system can exhibit chaotic oscillations under transverse magnetic fields and an electric field.The time-delayed feedback method was applied to stabilize the unstable periodic orbits (UPOs) embedded in the chaotic attractor.A bifurcation specified by a successive decrease in the number of UPOs with delayed time and feedback strength was revealed,indicating the stabilization of UPOs under feedback control.Noticeably,the introduction of a feedback perturbation will sometimes induce chaotic states that do not exist in the unperturbed system. 相似文献
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The n+ self-aligned-gate technology for high-performance AlGaAs/GaAs heterostructure FETs employing rapid lamp annealing have been studied. The large transconductance of 330 mS/mm at 300 K and 530 mS/mm at 83 K was obtained for the 0.7 ?m gate length device, by reducing the source resistance to 0.6 ?mm. The minimum delay time of 18.7 ps was obtained with a power dissipation of 9.1 mW at 300 K. The standard deviation of the delay time was as small as 1.1 ps at a fixed bias of 2.5 V. 相似文献
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《Electron Devices, IEEE Transactions on》1986,33(5):620-624
p-channel modulation-doped AlGaAs-GaAs heterostructure FET's (p-HFET's) employing two-dimensional hole gas (2DHG) were fabricated under various geometrical device parameter conditions. The p-HFET characteristics were measured at 300 and 77 K for the following three device-parameter ranges: the gate length Lg (1-320 µm), the gate-source distance Lgs (0.5-5 µm), and the layer thickness dt (35-58 nm) of AlGaAs beneath the gate. Based on the obtained results, a high-performance enhancement-mode p-HFET was fabricated with the following parameters:L_{g} = 1 µm,L_{gs} = 0.5 µm, andd_{t} = 35 nm. The achieved extrinsic transconductance gm was 75 mS . mm-1at 77 K. This experimental result indicates that a gm greater than 200 mS . mm-1at 77 K Can be obtained in 1-µm gate p-HFET devices. 相似文献
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本文采用理论模型研究了GaAs/AlGaAs 异质结中的非线性行为。在外加电场和磁场的共同作用下系统可以展现出混沌行为。我们采用延迟反馈法控制镶嵌在混沌吸引子中的不稳定周期。随着反馈强度和反馈时间的变化,系统发生一系列的分叉行为,表明不稳定周期轨道可以被稳定控制住。特别是随着反馈的加入也会导致系统走向新的混沌状态。 相似文献
19.
Studies of high-speed metal-semiconductor-metal photodetector witha GaAs/AlGaAs/GaAs heterostructure
Lu J. Surridge R. Pakulski G. van Driel K. Xu J.M. 《Electron Devices, IEEE Transactions on》1993,40(6):1087-1092
A GaAs/AlGaAs/GaAs heterostructure metal-semiconductor-metal photodetector (HMSM) with an active area of 100 μm×100 μm was developed and studied. The measured risetime of the device is 30 ps. The measured falltime is as short as 23 ps. The observed ultrafast response is attributed to the reduction of both the carrier transit time and the device capacitance due to the incorporation of the AlGaAs barrier layer. The HMSM is found to have a smaller saturation capacitance and saturates at a much lower bias voltage in comparison with the conventional MSM photodetector (CMSM). At a bias of 10 V, the full width at half maximum (FWHM) of the temporal response of the HMSM is more than 20% smaller than that of the CMSM. In addition, it is found that the peak impulse response for the HMSM is substantially larger than that of the CMSM under the same operation condition. Two-dimensional and equivalent circuit analyses were carried out to interpret the observed phenomena and to provide insight into the underlying physics 相似文献
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D. Schulte S. Subramanian L. Ungier K. Bhattacharyya J. R. Arthur 《Journal of Electronic Materials》1995,24(4):359-363
A study of the mobility of a novel modulation doped heterostructure in which the channel region is made of low-temperature
molecular beam epitaxially grown GaAs (LT-GaAs) and all other layers are grown at normal temperatures is presented for the
first time. The resistivity of the as-grown samples(in- situ annealed) is very high, as is that of single layers of bulk LT-GaAs. However, in the presence of light, the resistivity of
the LT-GaAs modulation-doped field effect transistor (MODFET) is significantly lower, facilitating reliable Hall measurements.
We speculate that the observed decrease in resistivity of the LT-GaAs MODFET is due to the formation of a two-dimensional
electron gas (2DEG) at the heterointerface under illumination. A number of samples grown under different growth conditions
were investigated. Mobilities for these samples were found to be in the range of 250 to 750 cm2Vs at 300K and ∼3000 to 5500 cm2Vs at 77K. A first-order computer simulation was implemented to calculate the mobility of the 2DEG using the relaxation-time
approximation to solve the Boltzmann equation, taking into account different scattering mechanisms. Scattering by the arsenic
clusters and by ionized impurities in the LT-GaAs MODFET channel are found to be the two dominant mechanisms limiting the
mobility of the LT-GaAs MODFET samples. Experimental values are in good agreement with theoretical results. 相似文献