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Optical study of Ba(Mn_xTi_(1-x)O_3) thin films by spectroscopic ellipsometry

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Chinese Physics B 2013年第11期22卷 589-593页

作者：张婷殷江丁玲红张伟风 National Laboratory of Solid State Microstructures Nanjing University Key Laboratory of Photovoltaic Materials of Henan Province School of Physics and Electronics Henan University

Stoichiometric Ba（MnxTi（1-x）O3）（BMT） thin films with various values of x were deposited on Si（111） substrates by the sol-gel technique. The influence of Mn content on the optical properties was studied by spectroscopic ellipsometry （SE） in the UV–Vis–NIR region. By fitting the measured ellipsometric parameter （Ψ and Δ） with a four-phase model （air/BMT＋voids/BMT/Si（111））, the key optical constants of the thin films have been obtained. It was found that the refractive index n and the extinction coefficient k increase with increasing Mn content due to the increase in the packing density. Furthermore, a strong dependence of the optical band gap Eg on Mn/Ti ratios in the deposited films was observed, and it was inferred that the energy level of conduction bands decreases with increasing Mn content.

关键词： Ba(MnxTi(1-x)O3) (BMT) thin films spectroscopic ellipsometry refractive index extinction co-efficient

Optical properties of InN studied by spectroscopic ellipsometry

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Journal of Semiconductors 2016年第10期37卷 16-20页

作者：叶春芽林伟周瑾李书平陈荔李恒吴小璇刘松青康俊勇 Fujian Provincial Key Laboratory of Semiconductors and Applications Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient Devices Department of Physics Xiamen University

With recently developed In N epitaxy via a controlling In bilayer, spectroscopic ellipsometry（SE） measurements had been carried out on the grown In N and the measured ellipsometric spectra were fitted with the Delta Psi2 software by using a suitable model and the dispersion rule. The thickness was measured by a scanning electron microscope（SEM）. Insight into the film quality of In N and the lattice constant were gained by X-ray diffraction（XRD）. By fitting the SE, the thickness of the In N film is consistent with that obtained by SEM cross-sectional thickness measurement. The optical bandgap of InN was put forward to be 1.05 e V, which conforms to the experimental results measured by the absorption spectrum and cathodoluminescence（CL）. The refractive index and the extinction coefficient of interest were represented for InN, which is useful to design optoelectronic devices.

关键词： InN spectroscopic ellipsometry refractive index extinction coefficient

Effects of interlayer coupling on the excitons and electronic structures of WS_(2)/hBN/MoS_(2) van der Waals heterostructures

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Nano Research 2022年第3期15卷 2674-2681页

作者： Xudan Zhu Junbo He Rongjun Zhang Chunxiao Cong Yuxiang Zheng Hao Zhang Songyou Wang Haibin Zhao Meiping Zhu Shanwen Zhang Shaojuan Li Liangyao Chen Key Laboratory of Micro and Nano Photonic Structures Ministry of EducationShanghai Engineering Research Center of Ultra-Precision Optical ManufacturingSchool of Information Science and EngineeringFudan UniversityShanghai 200433China State Key Laboratory of ASIC and System School of Information Science and EngineeringFudan UniversityShanghai 200433China Laboratory of Thin Film Optics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China Grating Technology Laboratory Changchun Institute of Optics and Fine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China State Key Laboratory of Applied Optics Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China

Inserting hexagonal boron nitride(hBN)as barrier layers into bilayer transition metal dichalcogenides heterointerface has been proved an efficient method to improve two dimensional tunneling optoelectronic device ***,the physical picture of interlayer coupling effect during incorporation of monolayer(1L-)hBN is not explicit *** this article,spectroscopic ellipsometry was used to experimentally obtain the broadband excitonic and critical point properties of WS_(2)/MoS_(2)and WS_(2)/hBN/MoS_(2)van der Waals *** find that 1L-hBN can only slightly block the interlayer electron transfer from WS_(2)layer to MoS_(2)***,insertion of 1L-hBN weakens the interlayer coupling effect by releasing quantum confinement and reducing efficient dielectric ***,the exciton binding energies in WS_(2)/hBN/MoS_(2)heterostructures blueshift comparing to those in WS_(2)/MoS_(2)*** this exciton binding energies tuning process,the reducing dielectric screening effect plays a leading *** the meantime,the quasi-particle(QP)bandgap remains unchanged before and after 1L-hBN insertion,which is attributed to released quantum confinement and decreased dielectric screening effects canceling each *** QP bandgap as along with blueshift exciton binding energies lead to the redshift exciton transition energies in WS_(2)/hBN/MoS_(2)heterostructures.

关键词： two-dimensional(2D)van der Waals heterostructure interlayer coupling excitons critical points spectroscopic ellipsometry

Semiconductor Multilayer Nanometrology with Machine Learning

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Nanomanufacturing and Metrology 2023年第2期6卷 37-54页

作者： Hyunsoo Kwak Jungwon Kim Korea Advanced Institute of Science and Technology(KAIST) Daejeon 34141South Korea

We review the measurement methods and thickness characterization algorithms of semiconductor multilayer ***’s ultrahigh-density,high-energy-efficient three-dimensional semiconductor devices require an iterative semiconductor layer-stacking *** determination of nanometer-scale layer thickness is crucial for reliable semiconductor device *** this paper,we first review the commonly used semiconductor multilayer thickness measurement methods,including destructive and nondestructive measurement ***,we review two approaches for thickness characterization:model-based algorithms using a physical interpretation of multilayer structures and a method using data-driven machine *** the growing importance of semiconductor multilayer devices,we anticipate that this study will help in selecting the most appropriate method for multilayer thickness characterization.

关键词： Semiconductor multilayer devices Electron microscopy Spectrophotometry spectroscopic ellipsometry Raman spectroscopy Thickness characterization Machine learning

spectroscopic ellipsometric study of the optical properties of Ag_2O film prepared by direct-current magnetron reactive sputtering

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Chinese Physics B 2010年第9期19卷 291-296页

作者：郜小勇冯红亮马姣民张增院 The Key Laboratory of Material Physics of Ministry of Education School of Physics and EngineeringZhengzhou University

The Ag2O film, as-dcposited by direct-current magnetron reactive sputtering at a substrate temperature of 150 ℃, clearly shows a preferential orientation （111）, and is capable of lowering the threshold value of the thermal decomposition temperature to about 200℃, which is helpful to its application in optical and magneto-optical storage. This paper fits its optical constants in terms of a general oscillator model by using measured ellipsometric parameters. The fitted oscillator energy 2.487 eV is close to the optical direct interband transition energy value of the Ag2O film determined by Tauc equation; whereas, the fitted oscillator energy 4.249 eV is far from the fitted plasma oscillator energy 4.756 eV by single-oscillator energy. The photoluminescence spectrum centred at about 2.31 eV indicates a direct-energy gap photoluminescence mechanism of the Ag2O film.

关键词： Ag2O film spectroscopic ellipsometry general oscillator model single-oscillator model

Highly c-Oriented Nanocolumn Structure ZnO Films on Sapphire Substrates by Pulsed Laser Deposition

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Chinese Physics Letters 2004年第4期21卷 747-749页

作者：刘志甫李永祥单福凯徐志华俞允植 TheStateKeyLaboratoryofHighPerformanceCeramicsandSuperfineMicrostructure ShanghaiInstituteofCeramicsShanghai200050 ElectronicCeramicsCenter DongeuiUniversityBusan614-714Korea

Highly c-oriented nanocolumn structure ZnO films were successfully deposited on sapphire (0001) substrates by pulsed laser deposition at a substrate temperature of 500 degrees C and 200mTorr oxygen pressure. X-ray diffraction, scanning electron microscopy, photoluminescence, and spectroscopic ellipsometry were used to characterize the ZnO films. The as-grown film is composed of well-aligned ZnO columns with diameters about 200–300nm. Photoluminescence spectrum of the ZnO film exhibits a strong near-band-edge emission and a weak deep-level emission band. The optical refractive indices and the extinction coefficients are obtained by fitting the spectroscopic ellipsometry data using the Forouhi–Bloomer dispersion relation.

关键词： spectroscopic ellipsometry

Study on electrical defects level in single layer two-dimensional Ta2O5

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Chinese Physics B 2016年第4期25卷 339-343页

作者：李大海宋雄飞胡林峰王子仪张荣君陈良尧张卫周鹏 Department of Optical Science and Engineering Fudan University Shanghai 200433 China ASIC & System State Key Laboratory School of Microelectronics Fudan University Shanghai 200433 China Department of Materials Science and Engineering Fudan University Shanghai 200433 China

Two-dimensional atomic-layered material is a recent research focus, and single layer Ta205 used as gate dielectric in field-effect transistors is obtained via assemblies of Ta205 nanosheets. However, the electrical performance is seriously affected by electronic defects existing in Ta2Os. Therefore, spectroscopic ellipsometry is used to calculate the transition energies and corresponding probabilities for two different charged oxygen vacancies, whose existence is revealed by x-ray photoelectron spectroscopy analysis. spectroscopic ellipsometry fitting also calculates the thickness of single layer Ta2Os, exhibiting good agreement with atomic force microscopy measurement. Nondestructive and noncontact spectroscopic ellipsometry is appropriate for detecting the electrical defects level of single layer Ta2O5.

关键词： single layer electronic defects spectroscopic ellipsometry

Deposition pressure effect on the surface roughness scaling of microcrystalline silicon films

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Chinese Physics B 2010年第10期19卷 403-407页

作者：朱志立丁艳丽王志永谷锦华卢景霄 School of Physical Engineering and Material Physics Laboratory Zhengzhou University

The scaling behaviour of surface roughness evolution of microcrystalline silicon （/zc-Si：H） films prepared by very- high frequency plasma-enhanced chemical vapour deposition （VHF-PECVD） has been investigated by using a spectroscopic eHipsometry （SE） technique. The growth exponent β was analysed for the films deposited under different pressures Pg. The results suggest that films deposited at Pg = 70 Pa have a growth exponent β about 0.22, which corresponds to the definite diffusion growth. However, abnormal scaling behaviour occurs in the films deposited at Pg = 300 Pa. The exponent β is about 0.81 that is much larger than 0.5 of zero diffusion limit in the scaling theory. The growth mode ofμc-Si：H deposited at Pg = 300 Pa is clearly different from that of μc-Si：H at Pg = 70 Pa. Monte Carlo simulations indicate that the sticking process and the surface diffusion of the radicals are two key factors to affect the growth mode under different pressures. Under Pg = 300 Pa, β〉 0.5 is correlated with the strong shadowing effect resulting from the larger sticking coefficient.

关键词： microcrystalline Si thin film spectroscopic ellipsometry the growth exponent MonteCarlo simulations

Tunable structural color of anodic tantalum oxide films

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Chinese Physics B 2012年第8期21卷 527-531页

作者：盛翠翠蔡云雨代恩梅梁长浩 Key Laboratory of Materials Physics and Anhui Key Laboratory of Nanomaterials and Nanotechnology Institute of Solid State PhysicsHefei Institutes of Physical ScienceChinese Academy of Sciences Information Center Hefei Institutes of Physical ScienceChinese Academy of Sciences

Tantalum （Ta） oxide flhns with tunable structural color were fabricated easily using anodic oxidation. The structure, components, and surface valence states of the oxide films were investigated by using gazing incidence X-ray diffractometry, X-ray photoelectron microscopy, and surface analytical techniques. Their thickness and optical properties were studied by using spectroscopic ellipsometry and total reflectance spectrum. Color was accurately defined using L＊a＊b＊ scale. The thickness of compact Ta2O5 films was linearly dependent on anodizing voltage. The film color was tunable by adjusting the anodic voltage. The difference in color appearance resulted from the interference behavior between the interfaces of air-oxide and oxide metal.

关键词： anodic tantalum oxide structural color spectroscopic ellipsometry optical interference