共查询到20条相似文献,搜索用时 15 毫秒
1.
Hongtao Jiang Minsky M. Keller S. Hu E. Singh J. DenBaars S.P. 《Quantum Electronics, IEEE Journal of》1999,35(10):1483-1490
InGaN-GaN represents an important heterostructure with applications in electronics and optoelectronics. It also offers a system where we can study the effects of interface roughness, alloy clustering, and the piezoelectric effect. In the paper, we examine how these factors influence the photoluminescence and excitation photoluminescence in InGaN-GaN quantum wells. We examine the Stokes shift as a function of the excitation level and doping and relate the values to the piezoelectric effect and disorder in the system. Detailed comparisons are made with experimental results 相似文献
2.
为了研究延伸波长In0.8Ga0.2As PIN短波红外探测器的温度响应光电特性,采用闭管扩散的平面型器件工艺,在金属有机化学气相外延(MOCVD)外延生长的NIN型InAs0.6P0.4/In0.8Ga0.2As/InAs0.6P0.4 buf./InP材料上制备了正照射延伸波长2561线列InGaAs红外焦平面探测器,研究了探测器在不同温度下的I-V特性、光谱响应特性和探测率。结果表明,随着温度的降低,在小偏压下,器件的正向暗电流由产生复合电流为主逐渐变为以扩散电流为主。在260~300 K温度范围内,反向电流主要由扩散电流和产生复合电流组成,当温度低于180 K时,器件的反向电流主要为隧穿电流。室温下器件响应截止波长和峰值波长分别为2.57 m和2.09 m,峰值探测率为7.25108 cmHz1/2/W,峰值响应率为0.95 A/W,量子效率为56.9%。焦平面的峰值探测率在153 K达到峰值,约为1.111011 cmHz1/2/W,响应非均匀性为5.28%。 相似文献
3.
Geels R.S. Thibeault B.J. Corzine S.W. Scott J.W. Coldren L.A. 《Quantum Electronics, IEEE Journal of》1993,29(12):2977-2987
The device design, material characterization, and performance of optimized vertical-cavity surface-emitting lasers (VCSELs) are presented. The basic design goal was to increase the output power of the lasers without greatly increasing the low threshold current reported in earlier devices. The material characterization was performed by measuring in-plane lasers and broad-area VCSELs made from the same material as the small VCSELs. For 10-μm-square devices, outputs over 3 mW, device operation over 100°C, 6% wall-plug efficiency, threshold voltages under 3 V, and threshold currents under mA are reported 相似文献
4.
Su K.-H. Hsu W.-C. Lee C.-S. Wu T.-Y. Wu Y.-H. Chang L. Hsiao R.-S. Chen J.-F. Chi T.-W. 《Electron Device Letters, IEEE》2007,28(2):96-99
This letter reports, for the first time, a high-electron mobility transistor (HEMT) using a dilute antimony In0.2Ga0.8 AsSb channel, which is grown by a molecular-beam epitaxy system. The interfacial quality within the InGaAsSb/GaAs quantum well of the HEMT device was effectively improved by introducing the surfactantlike Sb atoms during the growth of the InGaAs layer. The improved heterostructural quality and electron transport properties have also been verified by various surface characterization techniques. In comparison, the proposed HEMT with (without) the incorporation of Sb atoms has demonstrated the maximum extrinsic transconductance gm,max of 227 (180) mS/mm, a drain saturation current density IDSS of 218 (170) mA/mm, a gate-voltage swing of 1.215 (1.15) V, a cutoff frequency fT of 25 (20.6) GHz, and the maximum oscillation frequency fmax of 28.3 (25.6) GHz at 300 K with gate dimensions of 1.2times200 mum2 相似文献
5.
Yi-Jen Chan Ming-Ta Kang 《Electron Device Letters, IEEE》1995,16(1):33-35
The linearities of pseudomorphic heterostructure Al0.3Ga0.7As/In0.2Ga0.8As doped-channel FETs (DCFETs) and HEMTs were evaluated by DC and RF testings. Due to the absence of parallel conduction in the doped-channel approach, as compared to the modulation-doped structure, a wide and flat device performance together with a high current density was achieved. This improvement of device linearity suggests that doped-channel designs are suitable for high frequency power device application 相似文献
6.
Ming-Ta Yang Yi-Jen Chan 《Electron Devices, IEEE Transactions on》1996,43(8):1174-1180
The linearities of pseudomorphic Al0.3Ga0.7As/In0.2Ga0.8As doped-channel FET's were characterized by comparing the characteristics of modulation-doped field-effect transistors (FET's) based on dc and microwave evaluations. By using an undoped high-bandgap layer beneath the gate, the so-called parasitic MESFET-type conduction, which is common in HEMT's, can therefore be eliminated in doped-channel designs. Therefore, a wide and flat device performance together with a high current driving capability can be achieved in DCFET's. This linearity improvement in device performance suggests that doped-channel designs are more suitable for application in microwave power devices 相似文献
7.
High-quality In0.2Ga0.8N epilayers were grown on a GaN template at temperatures of 520 and 580℃ via plasma-assisted molecular beam epitaxy. The X-ray rocking curve full widths at half maximum (FWHM) of (10.2) reflections is 936 arcsec for the 50-nm-thick InGaN layers at the lower temperature. When the growth temperature increases to 580℃, the FWHM of (00.2) reflections for these samples is very narrow and keeps similar, while significant improvement of (10.2) reflections with an FWHM value of 612 arcsec has been observed. This improved quality in InGaN layers grown at 580℃ is also reflected by the much larger size of the crystalline column from the AFM results, stronger emission intensity as well as a decreased FWHM of room temperature PL from 136 to 93.9 meV. 相似文献
8.
K.H. Shim Y.-H. Kil H.K. Lee M.I. Shin T.S. Jeong S. Kang C.-J. Choi T.S. Kim 《Materials Science in Semiconductor Processing》2011,14(2):128-132
The optical property was studied on the Si0.8Ge0.2/Si strained multiple quantum well (MQW) structure grown using ultra-high vacuum chemical vapor deposition (UHV-CVD). Three peaks are observed in Raman spectrum, which are located at about 510, 410, and 300 cm−1, corresponding to the vibration of Si–Si, Si–Ge, and Ge–Ge phonons, respectively. The photoluminescence (PL) spectrum originates from the radiative recombinations both from the Si substrate and the Si0.8Ge0.2/Si MQW. For Si0.8Ge0.2/Si strained MQW, the transition peaks related to the MQW region observed in the photocurrent (PC) spectrum were preliminarily assigned to electron–heavy hole (e–hh) and electron–light hole (e–lh) fundamental excitonic transitions. 相似文献
9.
M.G.W. Alexander M. Nido W.W. Rühle R. Sauer K. Ploog K. Khler W.T. Tsang 《Solid-state electronics》1989,32(12):1621-1625
The electron transfer from a narrow to a wide quantum well through a thin barrier is studied in the non-resonant case by time-resolved photoluminescence. The two systems In0.53Ga0.47As/InP and GaAs/Al0.35Ga0.65As are compared. Space charge effects are investigated and discussed. Contributions of holes to the tunneling process are determined. 相似文献
10.
Ng B.K. David J.P.R. Plimmer S.A. Rees G.J. Tozer R.C. Hopkinson M. Hill G. 《Electron Devices, IEEE Transactions on》2001,48(10):2198-2204
The avalanche multiplication characteristics of Al0.8Ga 0.2As have been investigated in a series of p-i-n and n-i-p diodes with i-region widths, w, varying from 1 μm to 0.025 μm. The electron ionization coefficient, α, is found to be consistently higher than the hole ionization coefficient, β, over the entire range of electric fields investigated. By contrast with AlxGa 1-xAs (x⩽0.6) a significant difference between the electron and hole initiated multiplication characteristics of very thin Al0.8Ga0.2As diodes (w=0.025 μm) was observed. Dead space effects in the diodes with w⩽0.1 μm were found to reduce the multiplication at low bias below the values predicted from bulk ionization coefficients. Effective α and β that are independent of w have been deduced from measurements and are able to reproduce accurately the multiplication characteristics of diodes with w⩾0.1 μm and breakdown voltages of all diodes with good accuracy. By performing a simple correction for the dead space, the multiplication characteristics of even thinner diodes were also predicted with reasonable accuracy 相似文献
11.
In this paper, the low-field carrier mobility is investigated for quasi-2D electrons in a n-doped In0.53Ga0.47As/InP single symmetric quantum well. An accurate variational scheme is developed in view to determine the subband structure in this lattice-matched heterostructure. In this scheme, the Schrödinger-Poisson coupled equations are solved observing adequate matching conditions at the heterointerfaces, as well as exchange-correlation corrections to the Hartree potential. The results allowed us to compute the main scattering rates. Some interchanges in these scattering rates were found with respect to the limitation of electron mobility by varying the well and the spacer widths. 相似文献
12.
《Electron Device Letters, IEEE》1997,18(11):550-552
In0.5(Al0.3Ga0.7)0.5 P/In0.2Ga0.8As single- and double-heterojunction pseudomorphic high electron mobility transistors (SH-PHEMTs and DH-PHEMTs) on GaAs grown by gas-source molecular beam epitaxy (GSMBE) were demonstrated for the first time. SH-PHEMTs with a 1-μm gate-length showed a peak extrinsic transconductance gm of 293 mS/mm and a full channel current density Imax of 350 mA/mm. The corresponding values of gm and Imax were 320 mS/mm and 550 mA/mm, respectively, for the DH-PHEMTs. A short-circuit current gain (H21) cutoff frequency fT of 21 GHz and a maximum oscillation frequency fmax of 64 GHz were obtained from a 1 μm DH device. The improved device performance is attributed to the large ΔEc provided by the In0.5(Al0.3Ga0.7)0.5P/In 0.2Ga0.8As heterojunctions. These results demonstrated that In0.5(Al0.3Ga0.7)0.5P/In 0.2Ga0.8As PHEMT's are promising candidates for microwave power applications 相似文献
13.
Shey-Shi Lu Chin-Chun Meng Yo-Sheng Lin Hai Lan 《Electron Devices, IEEE Transactions on》1999,46(1):48-54
The effect of gate recess profile on device performance of Ga0.51In0.49P/In0.2Ga0.8As doped-channel FETs was studied. In the experiment, Ga0.51In 0.49P/In0.2Ga0.8As doped-channel FETs (DCFET's) using triple-recessed gate structure were compared with devices using single-recessed and double-recessed gate structures. It is found that triple-recessed gate approach provides higher breakdown voltage (35 V) than single-recessed (16 V) and double-recessed gate (28 V) approaches. This is attributed to the larger aspect ratio in the triple-recessed gate structure. A unified method to calculate the breakdown voltages of MESFETs, HEMTs and DCFETs (or MISFETs) of any given arbitrary recessed gate profile was proposed and used to explain the experimental results 相似文献
14.
Hsien-Chin Chin Ming-Jyh Hwu Shih-Cheng Yang Yi-Jen Chan 《Electron Device Letters, IEEE》2002,23(5):243-245
Surface passivation technology plays an important role, especially in E-mode pHEMTs applications, and a new passivation technology has been proposed in this study. This novel benzocyclobutene (BCB) passivation layer takes advantage of the low dielectric permittivity (2.7) and a low loss tangent (0.0008). In this letter, we not only suppress the gate-to-drain leakage current but also improve the device power performance under a high input power swing by using a BCB passivation layer. The passivated 1.0 μm-long gate pHEMTs exhibit a better off-state performance than the unpassivated ones. The maximum output power under a 2.4-GHz operation is 118 mW/mm, with a linear power gain of 11.1 dB and a power-added efficiency is 60% 相似文献
15.
Li W.Q. Karakucuk M. Freeman P.N. East J.R. Haddad G.I. Bhattacharya P.K. 《Electron Device Letters, IEEE》1993,14(7):335-337
The authors have measured the high-frequency characteristics and temporal response of a GaAs/AlGaAs heterojunction phototransistor with a GaAs/Al0.2Ga0.8 multi-quantum-well collector. The quantum wells offer tunability of the photoresponse (10 nm for a bias change of 4 V) and a negative differential resistance in the photocurrent-voltage characteristics. Measured values of f T and f max are 20 and 6 GHz, respectively. The temporal response to short-pulse optical excitation is characterized by a linewidth of 46 ps. Such devices are attractive candidates for making optically induced oscillators 相似文献
16.
Shoji H. Uchida T. Kusunoki T. Matsuda M. Kurakake H. Yamazaki S. Nakajima K. Ishikawa H. 《Photonics Technology Letters, IEEE》1994,6(10):1170-1172
A uniform In0.05Ga0.95As ternary substrate was grown by using liquid encapsulated Czochralski (LEC) technique with a method of supplying GaAs source material at a constant temperature, and InGaAs/InGaAsP strained single quantum well (SQW) lasers were fabricated on the substrate for the first time. The lasers lased at 1.03 μm and exhibited low threshold current density of 222 A/cm2 and excellent characteristic temperature of 221 K, showing that the ternary substrate has a sufficient quality for laser fabrication 相似文献
17.
Experimental and theoretical characterization of a series of strained InGaAs/InGaAs quantum well heterostructures is presented. Measurements of X-ray diffraction on calibrated pairs of samples are in excellent agreement with simulated X-ray spectra and provide precise values for compositions and layer thicknesses. With these parameters, the authors have calculated the light- and heavy-hole to electron transition wavelengths, taking into account quantum confinement effects and the influence of strain on the strained-layer bandgap and on the band offset at the lattice-mismatched heterointerface. These calculated bandgaps are in good agreement with the measured room temperature photoluminescence spectra 相似文献
18.
An investigation of multiple-quantum-well heterojunction phototransistors with InGaAs/InP quantum wells in the collector and InGaAsP base is discussed. The design of the structure ensures that light is absorbed only in the quantum-well region, thus providing a way to study the correlation between quantum well and phototransistor carrier dynamics. Moreover, since the operation of a n-p-n phototransistor is governed by hole injection into the base, the transient behavior of the device reflects the hole dynamics in the multiple-quantum-well region. The response of the device to picosecond optical pulses shows strong dependence on bias conditions: from device response determined by minority carrier recombination time (~2 ns) at high base-emitter bias, to current time constant dominated response (~50 ps) at low base-emitter bias. The field dependent escape times of carriers from the quantum wells under different bias conditions are obtained (10-100 ps) and are seen to affect the risetime of the transistor to pulsed photoexcitation 相似文献
19.
Chih-Hsiang Lin Meese J.M. Yia-Chung Chang 《Quantum Electronics, IEEE Journal of》1994,30(5):1234-1240
We present our optimization of a normally off refractive GaAs/Al xGa1-xAs multiple-quantum-well (MQW) reflection modulator with respect to the on/off reflectance change, on/off contrast ratio, and operating voltage. We use optical transfer matrices, theoretically calculated refractive indices, and absorption coefficients to simulate the operation of a normal-incident Fabry-Perot MQW modulator. Our calculations suggest that a normally off refractive GaAs/Al0.2Ga0.8As MQW reflection modulator with a reflectance change of 42.9% and an on/off contrast ratio of 1539 for an operating voltage of only 2.44 V can be fabricated by molecular-beam epitaxy (MBE) 相似文献
20.
Negative differential resistance has been observed in the current/voltage characteristics of a double barrier resonant tunnelling structure with Al0.2Ga0.8As emitters, Al0.4 Ga0.6As barriers and GaAs quantum well for the first time. The NDR becomes clear at low temperatures below 77 K, and the current/voltage characteristic is asymmetric. Results demonstrate that high-quality abrupt GaAs-AlxGa1-xAs-AlyGa1-yAs heterojunctions can be of use in resonant tunnelling structures 相似文献