共查询到20条相似文献,搜索用时 15 毫秒
1.
文章研究了GaN基共振隧穿二极管 (RTD) 的退化现象. 通过向AlGaN/GaN/AlGaN量子阱中引入三个实测的深能级陷阱中心并自洽求解薛定谔方程和泊松方程, 计算并且讨论了陷阱中心对GaN基RTD的影响. 结果表明, GaN基RTD的退化现象是由陷阱中心的缺陷密度和激活能的共同作用引起. 由于陷阱中心的电离率和激活能的指数呈正相关关系, 因此具有高激活能的陷阱中心俘获更多电子, 对负微分电阻 (NDR) 特性的退化起主导作用.
关键词:
共振隧穿二极管
GaN
陷阱中心
电离率 相似文献
2.
Influence of spacer layer thickness on the current-voltage characteristics of pseudomorphic AlAs/In0.53Ga0.47As/InAs resonant tunnelling diodes 下载免费PDF全文
This paper investigates the dependence of current voltage characteristics of AlAs/In0.53Ga0.47As/InAs resonant tunnelling diodes (RTDs) on spacer layer thickness. It finds that the peak and the valley current density J in the negative differential resistance (NDR) region depends strongly on the thickness of the spacer layer. The measured peak to valley current ratio of RTDs studied here is shown to improve while the current density through RTDs decreases with increasing spacer layer thickness below a critical value. 相似文献
3.
Jrg Malindretos Arno Frster Klaus Michael Indlekofer Mihail Ion Lepsa Hilde Hardtdegen Roland Schmidt Hans Lüth 《Superlattices and Microstructures》2002,31(6):315
A planar process for molecular beam epitaxy grown resonant tunnelling diodes (RTDs) in the GaAs/AlAs material system is presented and analysed with respect to the homogeneity of the diodes. The results can be correlated with a parameter sensitivity study based on quantum mechanical transport simulations. The homogeneity analysis reveals that our concept provides sufficient precision to fabricate RTDs suitable for application in robust digital logic circuits. 相似文献
4.
A bistable, self-latching inverter by the monolithic integration of resonant tunnelling diode and high electron mobility transistor 下载免费PDF全文
This paper reports that the structures of AlGaAs/InGaAs high electron mobility
transistor (HEMT) and AlAs/GaAs resonant tunnelling diode (RTD) are epitaxially
grown by molecular beam epitaxy (MBE) in turn on a GaAs substrate. An
Al0.24Ga0.76As chair barrier layer, which is grown adjacent to the top
AlAs barrier, helps to reduce the valley current of RTD. The peak-to-valley current
ratio of fabricated RTD is 4.8 and the transconductance for the 1-μm gate HEMT
is 125mS/mm. A static inverter which consists of two RTDs and a HEMT is designed and
fabricated. Unlike a conventional CMOS inverter, the novel inverter exhibits
self-latching property. 相似文献
5.
Yu. N. Buzynin Yu. N. Drozdov M. N. Drozdov A. Yu. Luk’yanov O. I. Khrykin A. N. Buzynin A. E. Luk’yanov E. I. Rau F. A. Luk’yanov 《Bulletin of the Russian Academy of Sciences: Physics》2008,72(11):1499-1503
New complex buffer layers based on a porous material have been developed for epitaxial growth of GaN films on Si substrates. The characteristics of gallium nitride heteroepitaxial layers grown on silicon substrates with new buffer layers by metal-organic vapor phase epitaxy are investigated. It is shown that the porous buffer layers improve the electric homogeneity and increase the photoluminescence intensity of epitaxial GaN films on Si substrates to the values comparable with those for reference GaN films on Al2O3 substrates. It is found that a fianite layer in a complex buffer is a barrier for silicon diffusion from the substrate into a GaN film. 相似文献
6.
7.
Nanoelectronic devices---resonant tunnelling diodes grown on InP substrates by molecular beam epitaxy with peak to valley current ratio of 17 at room temperature 下载免费PDF全文
This paper reports that InAs/In$_{0.53}$Ga$_{0.47}$As/AlAs resonant tunnelling diodes have
been grown on InP substrates by molecular beam epitaxy. Peak to valley
current ratio of these devices is 17 at 300K. A peak current density of
3kA/cm$^{2}$ has been obtained for diodes with AlAs barriers of ten
monolayers, and an In$_{0.53}$Ga$_{0.47}$As well of eight monolayers with
four monolayers of InAs insert layer. The effects of growth interruption for
smoothing potential barrier interfaces have been investigated by high
resolution transmission electron microscope. 相似文献
8.
V. V. Bel’kov Yu. V. Zhilyaev G. N. Mosina S. D. Raevskii L. M. Sorokin M. P. Shcheglov 《Physics of the Solid State》2000,42(9):1606-1609
The structure of bulk GaN layers grown on (0001) sapphire substrates by vapor-phase epitaxy has been studied by x-ray diffraction and transmission electron microscopy (TEM). It is found that these layers contain grown-in and screw dislocations. The dislocation density decreases away from the interface. The effect of an amorphous buffer layer on the formation of the initial GaN layer and, thus, on the degree of perfection of gallium nitride layers is elucidated. A model of generating grown-in dislocations and the relaxation mechanism of misfit stresses are proposed. 相似文献
9.
Tsutomu Minegishi Takuma Suzuki Chihiro Harada Hiroki Goto Meoung-Whan Cho Takafumi Yao 《Current Applied Physics》2004,4(6):685-687
GaN films were grown on ZnO substrate under various beam equivalent pressure ratios by plasma-assisted molecular beam epitaxy (P-MBE). We theoretically calculated the thermal stress caused by the difference of thermal expansion coefficients between GaN and ZnO. The changes of stress and critical thickness were evaluated by measurement of XRD for HT GaN and LT GaN buffer grown under Ga-rich and N-rich conditions. From this study, we observed that GaN grown under Ga-rich condition causes GaN film to under compressive-stress, while GaN grown under N-rich condition was tensile-stressed. Consequently, interdiffusion has no effect on the variation of the critical thickness. 相似文献
10.
In this study, we report growth and characterization of GaN layers on (1 0 0)- and (1 1 1)-oriented silicon-on-insulator (SOI) substrates. Using metalorganic chemical vapor deposition (MOCVD) technique, GaN layers are grown on KOH treated Si (1 0 0) overlayers of thin SIMOX SOI substrates. Growth of GaN on such surface with an AlN buffer leads to c-axis orientated textured GaN. This is evident from high-resolution X-ray diffraction (HRXRD) measurement, which shows a much broader rocking curve linewidth. Significantly enhanced photoluminescence (PL) intensity and partial stress relaxation is observed in GaN layers grown on these SOI substrates. Furthermore, GaN grown on (1 1 1)-oriented bonded SOI substrates shows good surface morphology and improved optical quality. Micro-Raman, micro-PL, and HRXRD measurements reveal single crystalline hexagonal GaN oriented along (0 0 0 1) direction. We also report growth and characterization of InGaN/GaN multi-quantum well structures on (1 1 1)-oriented bonded SOI. Such an approach to realize nitride epilayers would be useful to fabricate GaN-based micro-opto-electromechanical systems (MOEMS) and sensors. 相似文献
11.
Yu. N. Drozdov M. N. Drozdov O. I. Khrykin V. I. Shashkin 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2010,4(6):998-1001
The features and results of X-ray diffraction analysis of GaN films are presented. The films are grown by metalorganic vapor-phase
epitaxy on c-plane sapphire substrates using GaN or AlN nucleation layers deposited at a low temperature. Measurements of
the twist angle and concentrations of Al
x
Ga1-x
N solid solutions are discussed in detail. 相似文献
12.
Takuma Suzuki Chihiro Harada Hiroki Goto Tsutomu Minegishi Agus Setiawan H. J. Ko Meoung-Whan Cho T. Yao 《Current Applied Physics》2004,4(6):643-646
We report on GaN growth on Zn-polar ZnO substrates using plasma-assisted molecular-beam epitaxy (P-MBE). Before GaN growth, ZnO substrate annealing conditions were optimized. Reflection high-energy electron diffraction (RHEED) patterns after low-temperature GaN buffer layer annealing changed from streaky to spotty, suggesting that zinc and oxygen atoms interdiffuse from the ZnO substrate into the GaN epilayer. This interdiffusion results in a mix-polar GaN epilayer. 相似文献
13.
在实验优化MBE工艺条件的基础上,采用蓝宝石(0001)邻晶面衬底制备出了具有较高质量的GaN薄膜.XRD分析表明邻晶面衬底生长的GaN薄膜晶体结构质量明显提高,AFM表征结果显示邻晶面生长的样品表面形貌显著改善.蓝宝石衬底GaN薄膜的瞬态光电导弛豫特性对比实验研究发现,常规衬底生长的GaN薄膜光电导弛豫特性出现双分子复合、单分子复合和弛豫振荡三个过程,持续时间分别为0.91,7.7和35.5ms;蓝宝石邻晶面衬底生长的GaN薄膜光电导弛豫过程主要是双分子复合和单分子复合过程,持续时间分别为0.78和14ms.理论分析表明MBE生长GaN薄膜的持续光电导效应主要起源于本生位错缺陷引发的深能级.
关键词:
邻晶面蓝宝石衬底
GaN薄膜
瞬态光电导
弛豫特性 相似文献
14.
Piezoelectric polarization and quantum size effects on the vertical transport in AlGaN/GaN resonant tunneling diodes 下载免费PDF全文
In this work,the electronic properties of resonant tunneling diodes(RTDs) based on GaN-AlxGa(1-x)N double barriers are investigated by using the non-equilibrium Green functions formalism(NEG).These materials each present a wide conduction band discontinuity and a strong internal piezoelectric field,which greatly affect the electronic transport properties.The electronic density,the transmission coefficient,and the current–voltage characteristics are computed with considering the spontaneous and piezoelectric polarizations.The influence of the quantum size on the transmission coefficient is analyzed by varying GaN quantum well thickness,Al_xGa_(1-x)N width,and the aluminum concentration x_(Al).The results show that the transmission coefficient more strongly depends on the thickness of the quantum well than the barrier;it exhibits a series of resonant peaks and valleys as the quantum well width increases.In addition,it is found that the negative differential resistance(NDR) in the current–voltage(I–V) characteristic strongly depends on aluminum concentration xAl.It is shown that the peak-to-valley ratio(PVR) increases with xAlvalue decreasing.These findings open the door for developing vertical transport nitrides-based ISB devices such as THz lasers and detectors. 相似文献
15.
Scanning electron microscopy (SEM) images, transmission electron microscopy (TEM) images, and selected-area electron diffraction (SAED) patterns showed that vertically well aligned GaN nanorods with c-axis-oriented crystalline wurzite structures were grown on Si(1 1 1) substrates by using hydride vapor phase epitaxy. The high-resolution TEM (HRTEM) images showed that the crystallized GaN nanorods contained very few defects and that they were consisted of , {0 0 0 1}, and { } facets. The formation mechanisms for the GaN nanorods grown on Si(1 1 1) substrates are described on the basis of the SEM, TEM, SAED pattern, and HRTEM results. 相似文献
16.
Miasojedovas S Butkus M Jursenas S Lucznik B Grzegory I Suski T 《Micron (Oxford, England : 1993)》2009,40(1):118-121
Luminescence properties of 100-mum thick GaN epilayers grown by hydride vapor phase epitaxy (HVPE) over three different substrates: high-pressure grown n-type bulk GaN (HP-n-GaN), high-pressure bulk GaN doped with magnesium (HP-GaN:Mg), and free-standing HVPE lifted-off from sapphire (FS-HVPE-GaN), were compared by means of one-photon and two-photon excitations. The contribution of carrier capture to nonradiative traps was estimated by the analysis of luminescence transients with carrier diffusion taken into account. The estimated values of carrier lifetime of about 3ns and diffusion coefficient of 1cm(2)/s indicate the highest quality of GaN epilayers on FS-HVPE-GaN substrates. 相似文献
17.
Template-based nanoscale epitaxy has been explored to realize high-quality GaN on Si(1 1 1) substrates. We have employed polystyrene-based nanosphere lithography to form the nano-hole array patterns on GaN/Si(1 1 1) template and then, subsequent regrowth of GaN is carried out by metalorganic chemical vapor deposition (MOCVD). During the initial growth stage of GaN on such nanopatterned substrates, we have observed formation of nanoislands with hexagonal pyramid shape due to selective area epitaxy. With further epitaxial regrowth, these nanoislands coalesce and form continuous GaN film. The overgrown GaN on patterned and non-patterned regions is characterized by high-resolution X-ray diffraction (HRXRD) and high-spatial resolution optical spectroscopic methods. Micro-photoluminescence (PL), micro-Raman scattering and scanning electron microscopy (SEM) have been used to assess the microstructural and optical properties of GaN. Combined PL and Raman data analyses show improved optical quality when compared to GaN simultaneously grown on non-patterned bulk Si(1 1 1). Such thicker GaN templates would be useful to achieve III-nitride-based opto- and electronic devices integrated on Si substrates. 相似文献
18.
GaN films were grown on sapphire substrates by laser-induced reactive epitaxy. The domains in the films were determined to be the Ga-polarity by the convergent beam electron diffraction (CBED) technique, while the adjacent matrices had the N-polarity. The domain boundaries were characterized as inversion domain boundaries (IDBs). An atomic structure of the IDB is proposed based on high-resolution transmission electron microscopy (HRTEM) investigations. Control of the polarity of GaN/sapphire films was achieved by suppressing the formation of IDBs with an interlayer of AlGaN and a low-temperature GaN buffer layer. 相似文献
19.
M.M. Bülbül S.R.P. Smith B. Obradovic T.S. Cheng C.T. Foxon 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,14(3):423-429
We report on Raman scattering measurements of all Raman-active phonons in wurtzite and zinc blende structure GaN epilayers
grown on GaAs (001), GaAs (111)A, and GaAs (111)B oriented substrates by means of molecular beam epitaxy (MBE). Raman spectra
are taken from these epilayers at room temperature and 77 K in backscattering geometry. The measured values of the phonon
frequencies are in agreement with other studies and with lattice dynamic calculations of phonon modes in GaN zinc blende and
wurtzite structures. We show that crystal quality is much better in samples grown on GaAs (111) substrates than in samples
grown on GaAs (001) substrates. The observation of disorder-activated modes gives information about sample quality. Comparison
of the spectra from different thickness epilayers shows that the GaN is more highly disordered close to the substrate, particularly
for the (001) substrates.
Received 16 July 1999 相似文献
20.
Y. Cordier S. Chenot M. Laügt O. Tottereau S. Joblot F. Semond J. Massies L. Di Cioccio H. Moriceau 《Superlattices and Microstructures》2006,40(4-6):359
We report on the growth by molecular beam epitaxy of AlGaN/GaN high electron mobility transistors (HEMTs) on Si(111)/ SiO2/polySiC substrates. The structural, optical, and electrical properties of these films are studied and compared with those of heterostructures grown on thick Si(111) substrates. Field effect transistors have been realized, and they demonstrate the potentialities of III–V nitrides grown on these advanced substrates. 相似文献