共查询到18条相似文献,搜索用时 125 毫秒
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通过显微光致发光技术和显微拉曼(Raman)技术研究了半绝缘GaAs (SI-GaAs)晶体的带边附近的发光. 在光荧光谱中,观察到在高于GaAs带边0.348eV处有一个新的荧光峰. 结合Raman谱指认此发光峰来源于GaAs的E0+Δ0能级的非平衡荧光发射. 同时, 通过研究E0+Δ0能级的偏振、激发光强度依赖关系,以及温度依赖关系说明E0+Δ0能级与带边E0共享了共同的导带位置Γ6,同时这也说明在GaAs中主要是导带的性质决定了材料的光学行为.同时,通过与n-GaAs和δ掺杂GaAs相比较,半绝缘GaAs晶体的E0+Δ0能级的发光峰更能反映GaAs电子能级高临界点E0+Δ0的能量位置和物理性质. 研究结果说明显微光致发光技术是研究半导体材料带边以上能级光学性质的一种非常有力的研究工具.
关键词:
半绝缘GaAs
显微光致发光
自旋轨道分裂 相似文献
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铜(Ⅰ)基金属卤化物作为新一代环境友好的发光材料受到了研究者的广泛关注。本文采用溶剂辅助结晶法设计制备了一种新型零维金属卤化物发光材料(C12H24O6)NaCuBr2。在365 nm激发下,该化合物呈现出半峰宽为346 nm的超宽带橙红色发射,光致发光量子产率为42.6%。基于低温光谱、激发波长依赖的发射光谱和理论计算研究表明,峰值700 nm处的超宽带发射来自于Cu+离子3d轨道和Br-离子4p轨道间相互作用形成的简并能级。在低温下,(C12H24O6)NaCuBr2的晶格畸变导致能级的简并度降低,其荧光发射包含峰值为629 nm和735 nm的两个发射带。在高能激发下,电子跃迁到(C12H24O6)NaCuBr2的更高能级S3而带来的发射与77 K下观测到... 相似文献
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对分子束外延生长带边激子发光的Si1-xGex/Si量子阱结构,通过Si离子自注入和不同温度退火,观测到深能级发光带和带边激子发光的转变.Si离子注入量子阱中并在600℃的低温退火,形成链状或小板式的团簇缺陷,它导致深能级发光带的形成,在850℃的高温退火后重新观测到带边激子发光.这种团簇缺陷的热离化能约为0.1eV,比Si中空穴或填隙原子缺陷的热激活能(约0.05eV)高.这表明早期文献中报道的深能级发光带是由类似的团簇缺陷产生的.
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B. A. Weinstein S. R. Stambach T. M. Ritter J. O. Maclean D. J. Wallis 《Physica E: Low-dimensional Systems and Nanostructures》2004,20(3-4):317
High-pressure photoluminescence (PL) experiments (at 9 K) are reported for GaAs1−xNx/GaAs quantum wells having N compositions (x=0.0025, 0.004) in the dilute regime where the GaAs1−xNx alloy conduction band (CB) evolves rapidly by incorporation of N-pair states. Under increasing pressure, the PL spectra exhibit several new N-pair features that derive from CB-resonant states at 1 atm. Two of these features appear strongly at sub-band-gap energies for P29 kbar in the x=0.0025 sample, but are absent for all pressures in the x=0.004 sample. Several competing PL assignments due to bound-exciton recombination at NNi pairs (i=1–4 is the anion separation) are considered in light of prior findings for N-doped (1017 cm−3) GaAs. The absence of certain PL features in the x=0.004 sample shows that N-pair states mix into the CB-continuum via a selective process, and this selectivity offers an important test for band-structure calculations in dilute GaAs1−xNx alloys. 相似文献
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A. Gueddim 《Applied Surface Science》2007,253(17):7336-7341
Theoretical investigations of the conduction band offset (CBO) and valence band offset (VBO) of the relaxed and pseudo-morphically strained GaAs1−xNx/GaAs1−yNy heterointerfaces at various nitrogen concentrations (x and y) within the range 0-0.05 and along the [0 0 1] direction are performed by means of the model-solid theory combined with the empirical pseudopotential method under the virtual crystal approximation that takes into account the effects of the compositional disorder. It has been found that for y < x, the CBO and VBO have negative and positive signs, respectively, whereas the reverse is seen when y > x. The band gap of the GaAs1−xNx over layer falls completely inside the band gap of the substrate GaAs1−yNy and thus the alignment is of type I (straddling) for y < x. When y > x, the alignment remains of type I but in this case it is the band gap of the substrate GaAs1−yNy which is fully inside the band gap of the GaAs1−xNx over layer. Besides the CBO, the VBO and the relaxed/strained band gap of two particular cases: GaAs1−xNx/GaAs and GaAs1−xNx/GaAs0.98N0.02 heterointerfaces have been determined. 相似文献
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Yingce YanQi Wang Xia ZhangWei Shu Junshuai LiYongqing Huang Xiaomin Ren 《Physica B: Condensed Matter》2012,407(1):112-115
First-principle plane-wave pseudopotential calculations using the density-functional theory within the local density approximation (LDA) have been carried out to investigate the structural, electronic and thermodynamic properties of zinc-blende dilute nitride GaP1−xNx alloy. We have found that the unit cell volumes of GaP1−xNx alloys are smaller than the value calculated from the linear interpolation of GaN and GaP binary alloys and there exists a negative deviation from Vegard's law. The Ga-P and Ga-N bond lengths of GaP1−xNx alloys reveal a slight relaxation. The incorporation of nitrogen into GaP leads to the giant reduction of the bandgap energy. We have investigated the thermal stabilities and obtained the most stable configurations of the GaP1−xNx alloy. In addition, the formation enthalpies have also been calculated, which could explain the difficulty in nitrogen incorporation into GaP. 相似文献
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R.D. Dupuis N. Holonyak M.G. Craford D. Finn W.O. Groves 《Solid State Communications》1973,12(6):489-493
For GaAs1?xPx:N crystal composition x < 0.8, the distinction between NN1 and NN3 transitions becomes blurred. Photoluminescence measurements on N-doped GaAs1?xPx layers (0.3 < x < 0.4) and, for comparison, on the same vapor epitaxial crystals with the N-doped layer removed, indicate that the NN3 transition reappears (and thus also the NN1 transition) as ENN3 approaches EΓ. This is attributed to the resonant enhancement that occurs when ENN ~ EΓ. 相似文献
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Previous neutron measurements in the mixed magnetic system, CsMn1-xCoxCl3·2H2O have been extended to samples with x = 0.035, 0.05 and 0.075. In this system two kinds of magnetic ions with competing orthogonal spin anisotropies are randomly distributed. The ordering temperatures TN (x are clearly detected through the appearance of magnetic Bragg reflections. However, there are no indications for the existence of any other phase transition under the experimental conditions. The observed magnetic phase below TN (x) corresponds to an oblique antiferromagnetic phase predicted for such a system. 相似文献
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Hafnium oxynitride (HfOxNy) gate dielectric has been deposited on Si (1 0 0) by means of radio frequency (rf) reactive sputtering using directly a HfO2 target in N2/Ar ambient. The thermal stability and microstructural characteristics for the HfOxNy films have been investigated. XPS results confirmed that nitrogen was successfully incorporated into the HfO2 films. XRD analyses showed that the HfOxNy films remain amorphous after 800 °C annealing in N2 ambient. Meanwhile the HfOxNy films can also effectively suppress oxygen diffusion during high temperature annealing and prevent interface layer from forming between HfOxNy films and Si substrates. AFM measurements demonstrated that surface roughness of the HfOxNy films increase slightly as compared to those pure HfO2 films after post deposition annealing. By virtue of building reasonable model structure, the optical properties of the HfOxNy films have been discussed in detail. 相似文献
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Wenxia Feng Shouxin Cui Haiquan Hu Guiqing Zhang Zengtao Lv 《Physica B: Condensed Matter》2011,406(19):3631-3635
The structural, electronic and elastic properties of TiCxN1−x, ZrxNb1−xC and HfCxN1−x alloys have been investigated by using the plane-wave pseudopotential method within the density-functional theory. The calculations indicate that the variations of the equilibrium lattice constants and bulk modulus with the composition are found to be linear. The calculated elastic constants C44 and shear constants as a function of alloy concentration reveal the anisotropic hardness of these compounds. The partial and total density of states (DOS) for the binary and ternary compounds had been obtained, and the metallic behavior of these alloys had been confirmed by the analysis of DOS. 相似文献