共查询到19条相似文献,搜索用时 203 毫秒
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利用低能电子衍射(LEED)、X射线光电子能谱(XPS)、电子能量损失谱(EELS)、紫外光电子能谱(UPS),对室温下Mn在GaAs(100)4×1表面的淀积过程进行了研究。研究结果表明,当锰的覆盖度θ≥0.25nm时,LEED图案完全消失,表明Mn没有生长成单晶。LEED,EELS的结果都表明淀积初期是层状生长的。对XPS的Ga2p3/2,As2p3/2的峰形、强度进行分析,可以知道在很小的覆盖度下,Mn就与衬底反应。置换出的Ga被局限在离原来的界面约3nm
关键词: 相似文献
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本文用X射线光电子能谱(XPS)和紫外光电子能谱(UPS)研究了CO与预覆盖Ne的Ag(110)表面的相互作用。低温下CO饱和吸附在Na/Ag(110)上存在两种吸附态,随衬底温度升高仅留下一种吸附态。实验结果表明,该吸附态与Ag(110)上存在的Na有关它是CO解离的前驱态。
关键词: 相似文献
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用紫外光电子能谱(UPS)研究了酞菁铜分子在Ag(110)单晶表面上的吸附,随着酞菁铜分子覆盖度增加,衬底Ag的3d电子信号逐渐减弱,在此能带区域出现两个新的谱峰,这两个与吸附有机分子轨道有关的谱峰的束缚能分别为4.45 和6.36 eV.随着覆盖度的增加,在结合能为1.51和9.20 eV处又出现了两个谱峰,它们同样来自吸附有机分子的轨道.随着覆盖度的继续增加,上述四个谱峰的强度逐渐增加,其能量位置均发生了明显的偏移.根据角分辨光电子能谱的实验结果,酞菁铜分子的分子平面基本与衬底表面平行.密度泛函理论计
关键词:
酞菁铜
紫外光电子谱
吸附电子态
密度泛函理论 相似文献
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用紫外光电子能谱(UPS)研究了酞菁铜分子在Ag(110)单晶表面上的吸附,随着酞菁铜分子覆盖度增加,衬底Ag的3d电子信号逐渐减弱,在此能带区域出现两个新的谱峰,这两个与吸附有机分子轨道有关的谱峰的束缚能分别为4.45 和6.36 eV.随着覆盖度的增加,在结合能为1.51和9.20 eV处又出现了两个谱峰,它们同样来自吸附有机分子的轨道.随着覆盖度的继续增加,上述四个谱峰的强度逐渐增加,其能量位置均发生了明显的偏移.根据角分辨光电子能谱的实验结果,酞菁铜分子的分子平面基本与衬底表面平行.密度泛函理论计 相似文献
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利用紫外光电子能谱(UPS)和低能电子衍射(LEED)对银(110)表面上perylene与tetracene的生长进行了研究.LEED的结果表明:一个分子单层的perylene在银(110)表面上会形成C(6×2)的有序结构;一个分子单层的tetracene,观察到的则是C(4×2)的有序结构.根据UPS的测量,与perylene分子轨道有关的4个特征峰分别位于Frimi能级以下35,48,64和85eV处,与tetracene分子轨道有关的4个特征峰的结合能分别为3.4,49,59和94eV.角分辨紫外光电子能谱(ARUPS)的测量表明,表面附近的perylene和tetracene分子平面平行于银衬底表面,tetracene分子的长轴可以确定沿[110]晶向.
关键词:
有机半导体材料
紫外光电子能谱
结构和电子结构 相似文献
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用X射线电子能谱(XPS)、热脱附谱(TDS)和紫外光电子能谱(UPS)方法研究了乙烯(C2 sub>H4)在Ru(1010)表面的吸附,在低温下(200K以下)乙稀(C2H4)可以在Ru(1010)表面上以分子状态稳定吸附,在200K以上乙烯(C2H 4)则发生了脱氢分解反应.TDS结果表明乙烯(C2H4)分 解后的主要产物为乙炔(C<
关键词:
乙烯
钌(1010)表面
吸附与分解 相似文献
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The adsorption and desorption of glycine (NH2CH2COOH), vacuum deposited on a NiAl(1 1 0) surface, were investigated by means of Auger electron spectroscopy (AES), low energy electron diffraction (LEED), temperature-programmed desorption, work function (Δφ) measurements, and ultraviolet photoelectron spectroscopy (UPS). At 120 K, glycine adsorbs molecularly forming mono- and multilayers predominantly in the zwitterionic state, as evidenced by the UPS results. In contrast, the adsorption at room temperature (310 K) is mainly dissociative in the early stages of exposure, while molecular adsorption occurs only near saturation coverage. There is evidence that this molecularly adsorbed species is in the anionic form (NH2CH2COO−). Analysis of AES data reveals that upon adsorption glycine attacks the aluminium sites on the surface. On heating part of the monolayer adsorbed at 120 K is converted to the anionic form and at higher temperatures dissociates further before desorption. The temperature-induced dissociation of glycine (<400 K) leads to a series of similar reaction products irrespective of the initial adsorption step at 120 K or at 310 K, leaving finally oxygen, carbon and nitrogen at the surface. AES and LEED measurements indicate that oxygen interacts strongly with the Al component of the surface forming an “oxide”-like Al-O layer. 相似文献
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The adsorption of naphthalene, vacuum deposited on a Ag(1 0 0) surface, was comprehensively investigated by means of low-energy electron diffraction (LEED), temperature-programmed thermal desorption (TPD) spectroscopy, X-ray photoelectron spectroscopy (XPS), and polarization-dependent near-edge X-ray absorption fine structure (NEXAFS) spectroscopy in the mono- and multilayer regime. A growth of long-range ordered monolayer at 140 K is observed with LEED. The polarization-dependent C 1s NEXAFS shows that the naphthalene molecules in the monolayer lie almost parallel to the Ag(1 0 0) surface. With increasing film thickness, the molecular orientation turns to upright position. Furthermore, NEXAFS measurements show that in the multilayer regime the molecular orientation depends on the substrate temperature during deposition. 相似文献
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高分辨率电子能量损失谱(HRFELS)能直接判定Al-GaAS(100)界面反应的生成物。本文结合X射线光电子能谱(XPS)的测量,采用HREELS来测量界面的禁带宽度,研究了Al-GaAs(100)(4×1)界面的形成过程。结果判定了室温下Al-GaAs(100)界面生成的为AlAs。而退火后,界面上生成AlCaAs合金。实验中还用低能电子衍射(LEED)观察了室温下Al在GaAs(100)(4×1)面上的淀积过程,发现随着Al淀积量的增加,表面是从无序到有序转化的。
关键词: 相似文献
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The adsorption of methanol on clean and oxygen dosed Cu(110) surfaces has been studied using temperature programmed reaction spectroscopy (TPRS), ultra-violet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS). Methanol was adsorbed on the clean surface at 140 K in monolayer quantities and subsequently desorbed over a broad range of temperature from 140 to 400 K. The UPS He (II) spectra showed the 5 highest lying emissions seen in the gas phase spectrum of methanol with a chemisorption bonding shift of the two highest lying orbitais due to bonding to the surface via the oxygen atom with which these orbitals are primarily associated. A species of quite a different nature was produced by heating this layer to 270 K. Most noticeably the UPS spectrum showed only 3 emissions and the maximum coverage of this state was approximately monolayer. The data are indicative of the formation of a methoxy species, thus showing that methanol is dissociated on the clean Cu(110) surface at 270 K. The same dissociated species was observed on the oxygen dosed surface, the main difference in this ease being the production of large amounts of H2CO observed in TPRS at 370 K. 相似文献
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We report here the growth of Ag film and its thermal stability on the TiO2(1 1 0)-(1×1) surface using combination techniques of low-energy ion scattering (LEIS), X-ray photoelectron spectroscopy (XPS), and low-energy electron diffraction (LEED). At a surface temperature as low as 125 K, a 2D growth of Ag films seems to occur for submonolayer coverages up to ∼0.8 ML. Annealing of low temperature grown Ag films to 500 K for coverage of 1–2.4 ML would result in the formation of metastable Ag layers with rest of Ag forming 3D needle-like islands on top of this Ag film. 相似文献
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The deposition of silver on an ordered alumina film prepared on Re(0001) surface has been studied by Auger electron spectroscopy (AES), low energy electron diffraction (LEED) and high resolution electron energy loss spectroscopy (HREELS). The results show that Ag grows initially as clusters at 90K and 300K. A red shift of the Ag surface plasmon as a function of decreasing coverage is observed, which is related to the cluster size effect. A surface plasmon characteristic of metallic Ag appears at coverages higher than 2.8 monolayer equivalent. 相似文献
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Oxygen adsorption on a Mo(111) surface is investigated at low pressures (10?7 to 10?5 Pa) and room temperature by Auger electron spectroscopy (AES), low-energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS) and ultra-violet photoelectron spectroscopy (UPS). In agreement with previous studies it is established that the surface is not reconstructed during adsorption and the oxygen forms no ordered structures. On the basis of kinetic and spectroscopy data, the formation of two adsorption states on the surface within 1 monolayer is established. The valence band of a clean surface is studied in detail. An attempt is made to ascribe the peaks obtained to definite d states. The interaction between O2 and Mo(111) is discussed in terms of the results obtained and a comparison with the O2/W(111) system is made. 相似文献
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We have studied the adsorption structure of acetic anhydride on a TiO2(1 1 0) surface using XPS (X-ray photoelectron spectroscopy), LEED (low energy electron diffraction) and HREELS (high resolution electron energy loss spectroscopy) to determine the origins of the unique adsorption properties of carboxylic acids on a TiO2(1 1 0) surface. The C 1s XPS data indicated that the saturation carbon amount of adsorbed acetic anhydride was 12 ± 3% larger than that of the adsorbed acetic acid. LEED showed p(2 × 1) weak spots for the acetic anhydride adsorbed surface. The HREELS spectra revealed the dissociative adsorption of acetic anhydride. Based on these findings, we concluded that the neutralization of the bridging oxygen atoms associated with the dissociative adsorption is necessary for the stable adsorption of carboxylates on the 5-fold Ti sites. 相似文献
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M. Frerichs 《Applied Surface Science》2006,253(2):950-958
Surface sensitive electron spectroscopy was applied to study the fundamental processes of aluminium corrosion. We used metastable induced electron spectroscopy (MIES) and ultraviolet photoelectron spectroscopy (UPS) for the investigation of the densities of states of surface and bulk, respectively. Furthermore we applied X-ray photoelectron spectroscopy (XPS) to investigate the chemical composition of the top surface layers. All measurements were performed under ultra high vacuum conditions.Al films with thicknesses of 7 nm were investigated. Both the interaction of oxygen and water with these films leads to the formation of an aluminium-oxygen layer, which is partly composed of stoichiometric Al2O3. Weak heat treatment at 770 K transforms the surface layer into Al2O3 with a thickness of about 2 nm. Further gas offer does not lead to an increase of this thickness, neither for oxygen nor for water. Additional to the oxygen offer, water exposure leads to the formation of OH species in the top aluminium-oxygen layer to a small amount. Weak heat treatment to 770 K removes this species completely. Water exposure leads to a much faster oxide formation than oxygen exposure. We try to give a model for the fundamental corrosion processes on a molecular scale. 相似文献