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21.
ZnSe heteroepitaxial layers have been grown on GaAs (100), (110) on axis, and (110) 6° miscut substrates by molecular beam
epitaxy. ZnSe on GaAs (110) shows smooth and featureless spectra from Rutherford backscattering channeling measurements taken
along major crystalline directions, whereas ZnSe on GaAs (100) without pre-growth treatments exhibit large interface disorder
in channeling spectra. ZnSe films grown on GaAs (110) on axis show facet formation over a wide range of growth conditions.
The use of (110) 6° miscut substrates is shown to suppress facet formation; and under the correct growth conditions, facet-free
surfaces are achieved. Etch pit density measurements give dislocation densities for ZnSe epitaxial layers grown on GaAs (100),
(110) on axis, and (110) 6° miscut substrates of 107/cm2, 3 × 105/cm2 and 5 × 104/cm2, respectively. These results suggest that with further improvements to ZnSe growth on GaAs (110)-off substrates it may be
possible to fabricate defect free ZnSe based laser devices. 相似文献
22.
介绍了一种结构更加简单的热壁外延装置,以及用该装置在GaAs(100)面上生长ZnSe单晶外延层的工艺。扫描电镜和X射线衍射分析表明用该装置生长的ZnSe单晶外延层是比较理想的。 相似文献
23.
K. C. Ku S. H. Chun W. H. Wang W. Fadgen D. A. Issadore N. Samarth R. J. Epstein D. D. Awschalom 《Journal of Superconductivity》2005,18(2):185-188
We describe the growth of modulation-doped ZnSe/(Zn,Cd)Se quantum wells on (110) GaAs substrates. Unlike the well-known protocol for the epitaxy of ZnSe-based quantum structures on (001) GaAs, we find that the fabrication of quantum well structures on (110) GaAs requires significantly different growth conditions and sample architecture. We use magnetotransport measurements to confirm the formation of a two-dimensional electron gas in these samples, and then measure transverse electron spin relaxation times using time-resolved Faraday rotation. In contrast to expectations based upon known spin relaxation mechanisms, we find surprisingly little difference between the spin lifetimes in these (110)-oriented samples in comparison with (100)-oriented control samples. 相似文献
24.
通过改进的溶剂热方法,以KBH4作为还原剂,在三乙胺溶液介质中制备了ZnSe纳米晶材料.与ZnSe体材料相比,其纳米材料的稳态吸收边发生了蓝移,而且纳米颗粒的尺寸越小,蓝移量越大,这是由于随着尺度减少而引起的量子限制效应增强造成的.对在溶液中的ZnSe纳米颗粒的超快吸收谱的研究表明,当纳米颗粒的平均尺寸为75nm时,电子-声子散射时间为8.74ps;当平均尺寸为45nm时,散射时间为2.77ps.随着纳米颗粒尺寸的减小,载流子与颗粒表面的非弹性碰撞几率增加,从而使载流子-声子耦合的强度增强,导致载流子-声子散射时间缩短. 相似文献
25.
Crystallographic quality and the lattice constant of ZnSe crystals grown from Te/ Se solutions by the temperature gradient
solution growth method were evaluated by using a high resolution x-ray diffractometer. The full width at half maximum of the
x-ray rocking curve was 5.7 sec, a value almost equivalent to that of GaAs. The distribution of crystallographic properties
along the growth direction was nearly the same excepting just on the heat-sink. The accurate lattice constant of the ZnSe
crystal measured by this system was 5.6700 ± 0.000025 A. 相似文献
26.
The metalorganic molecular beam epitaxial growth of ZnSe using diethylzinc and/or diethylselenium gas sources results in an
abnormally low growth rate of several hundred angstroms per hour. Experiments with dimethylzinc or elemental zinc with elemental
selenium confirm that adsorbed ethyl-based radicals contribute to the low growth rate. Surface sites for incorporation of
the metal atom are saturated by the chemisorbed ethyl radicals or by an ethyl molecule that is postulated to cause the growth
rate limitation. It is observed that laser and electron beam irradiation overcome the site blockage phenomenon under appropriate
growth conditions. For beam-assisted growth, significant increases over the unilluminated growth rate are measured. Experiments
designed to investigate the wavelength dependence of the photon-enhanced growth rate provide evidence that photo-generated
electron/hole pairs are necessary to assist in releasing the ethyl radical from the unpyrolyzed DEZn molecule that is adsorbed
to the surface. 相似文献
27.
对用原子层外延方法,在[001]晶向GaAs衬底上生长的[(Cdse)m(Znse)n]p-ZnSe应变量子阱结构,在10~300K温度范围内测量了喇曼散射光谱,观察到两种类ZnSeLO声子限制模.利用改变样品温度和入射光能量实现了共振喇曼散射,观察到高达7阶的类ZnSeLO声子模.并讨论了多声子喇曼散射和热萤光过程的区别. 相似文献
28.
S.K. Chan S.K. Lok G. Wang Y. Cai N. Wang I.K. Sou 《Journal of Electronic Materials》2008,37(9):1344-1348
Nanotrenches are induced by thermal annealing Au droplets on ZnSe surfaces. High-resolution scanning electron microscopy studies
of the nanotrench structures reveal that the preferred migration directions of the catalyst droplets are along the direction family. On a ZnSe(111)B surface, each of the trenches is along one of the six directions while on a nonvicinal ZnSe(100) surface, the trenches are along a pair of antiparallel directions. Based on the results obtained from atomic force microscopy surface profiling and electron energy-loss spectroscopy
chemical analysis techniques, a model is proposed to describe the possible formation mechanisms of the␣observed nanotrenches.
The highly parallel nanotrenches induced on the Au/ZnSe(100) structure as revealed in this study are potentially useful as
a template for in situ fabrication of ordered one-dimensional nanostructures (such as nanowires) of many materials. 相似文献
29.
室温下利用阴极荧光光谱技术对ZnSe晶体进行了350~850 nm的无损全光阴极荧光图谱检测,分析了晶体内部缺陷及夹杂情况,室温下测得ZnSe晶体在400~550 nm的阴极荧光光谱,阴极荧光光谱测得462 nm处的ZnSe本征发光峰。缺陷处测得462 nm的本征发光峰和453 nm的缺陷发光峰,结合能谱分析,ZnSe晶体表面缺陷处的Zn:Se比约为6:4。阴极荧光图谱中缺陷处发光峰主要来自Zn夹杂缺陷发光。 相似文献
30.
Susanne Siebentritt Philipp Walk Ulrich Fiedeler Iver Lauermann Kari Rahne Martha Ch. Lux‐Steiner Thomas P. Niesen Franz Karg 《Progress in Photovoltaics: Research and Applications》2004,12(5):333-338
ZnSe prepared by metal organic chemical vapor deposition is used as a buffer layer in Cu(In,Ga)(S,Se)2 solar cells without any utilization of wet chemistry. Cell efficiencies are as good as cells with the conventional CdS buffer. Stability of unencapsulated cells under damp heat conditions is somewhat lower for the alternative buffer. The first stages of photoassisted growth are studied. X‐ray photoemission spectroscopy shows that a continuous layer is formed. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献