摘要
摘要
PtSe2是一种新型的过渡金属硫化物，具有室温下超高的载流子迁移率，空气中较高的稳定性等优良的物理性质。此外，其能带结构、吸收光谱、拉曼光谱都表现出明显的厚度依赖特性，当其由块状逐渐减薄至单层时，PtSe2将由半金属逐步过渡为半导体。这些优良的性质使得PtSe2在光电器件领域具有广泛的应用前景。在对基于PtSe2的光电器件进行设计和性能分析时，我们需要对其线性光学性质和光学常数有深度的理解和掌握。光学常数谱能反映材料的线性光学性质。椭偏仪可以同时对薄膜的光学常数和厚度进行测量，并且具有精确度高、无破坏性等优点，被广泛应用于光学薄膜的测量。本文通过光谱椭偏对化学气相沉积制备的不同厚度的PtSe2薄膜的光学性质和光学常数进行了研究。具体内容如下：
首先，我们通过光学显微镜和原子力显微镜表征了样品的平整度。接下来X射线光电子能谱确认了样品中的组分，测量结果表明我们的样品仅由Pt、Se 两种元素组成，并且样品表现为P型掺杂。拉曼光谱表征了样品的晶格结构，结果表明所测样品是高质量的PtSe2薄膜。吸收谱、电输运以及傅里叶变换红外透射谱测量的结果表明样品中同时存在半金属相和半导体相。偏振光学显微测量以及偏振吸收测量结果显示样品在143×108 µm2平面范围内表现为各向同性的光学响应。接下来，我们用椭偏仪测量了样品的椭偏参数ψ和Δ，并通过建立光学模型和数据拟合得到了样品的光学常数（n和κ）、复介电函数（ε1和ε2）
以及样品的厚度。最后，我们综合以上的实验结果进行了分析和讨论，结果表明化学气相沉积制备的10层以内的PtSe2的光学常数随厚度变化具有明显的依赖性。研究结果为后续进行精确的光学分析和数值模拟提供了重要的参数，并且有助于PtSe2的进一步研究和在光电子器件上的应用。
关键词：PtSe2；过渡金属硫化物；光学常数；椭偏仪；傅里叶变换红外光谱
I
Abstract
Abstract
PtSe2, an emerging 2D group-10 transition metal dichalcogenide (TMD), shows high carrier mobility at room temperature and high stability in the air. Besides, the band structure, absorption spectrum and raman spectrum of PtSe2 films show strong dependence on the thickness. When it going from bulk to few-layer, PtSe2 undergoes a mimetal-to-miconductor transition. The excellent properties make PtSe2 show a wide application prospect in the field of photoelectric devices. The design and performance analysis of photoelectric devices bad on PtSe2require depth understanding on its linear optical properties and optical constant. The optical constant spectrum ca
n reflect the linear optical properties of PtSe2. Spectroscopic ellipsometry is a nsitive (~0.1 Å) and nondestructive technique to measure the optical constant and thickness of 2D materials. Benefitting by the properties of high accuracy and nondestructive, spectroscopic ellipsometry is widely ud in the measurement of optical thin films. The following works were done to measure the optical properties and optical constant of chemical vapor deposition-grown PtSe2 with different thickness.
Firstly, the flatness of the samples were measured by optical microscope and atomic force microscope. Then, the x-ray photoemission spectroscopy confirmed the composition of the sample, which showed that our samples are compod of only Pt and Se elements. Besides, the Se:Pt stoichiometric ratios indicated the p-type doping in the films. The lattice structure of the samples were characterized by raman spectrum, which evinced the high quality of samples. The measured absorption spectra, Fourier transform infrared spectroscopy and electrical transport characterization reveal the coexistence of both miconducting and metallic contents in the PtSe2films. Polarized optical microscopy and polarization absorption measurements reveal the isotropic in-plane optical respon of the continuous PtSe2 films in a scale size of at least as small as 143×108 µm2. Finally, parameters ψand Δof the samples were obtained by spectroscopic ellipsometry. The optical
II
Abstract
constant, including refractive index n, extinction coefficient κ, complex dielectric constant (ε1and ε2) as well as thickness of the samples were extracted by data fitting. The values of n and κof PtSe2 were found to have a strong dependence on the thickness and they decrea as the reduction of the thickness. The tunable optical constants are conducive to provide vital parameters for preci optical analysis and analog simulation, promoting future developments and applications of PtSe2.
高兴的拼音微信好听名字Key Words: transition metal dichalcogenides; PtSe2; optical constants; spectroscopic ellipsometry; Fourier transform infrared spectra
III
目录
目录
摘要 ............................................................................................................ I I 目录 ......................................................................................................... IV 第一章绪论 (1)
第一节二维材料简介 (1)
第二节二维材料光学性质的研究 (3)
1.2.1 石墨烯光学性质的研究 (3)
向天果的功效与作用1.2.2 二维过渡金属硫化物光学性质的研究 (5)
1.2.3 PtSe2的基本性质 (8)
第三节本论文的研究内容及意义 (15)
第二章椭偏仪测量原理及其应用 (16)
第一节光学常数 (16)
2.1.1 光学常数简介 (16)
2.1.2 光学常数的测量方法 (18)
第二节椭偏仪测量原理―菲涅尔反射公式 (19)
英俄战争
2.2.1 菲涅尔反射公式 (19)
旅游去处
2.2.2 椭偏仪测量原理 (21)
第三节椭偏仪的发展和应用 (21)
2.3.1 椭偏技术的诞生和发展 (21)
2.3.2 椭偏仪的应用 (22)
第四节本章小结 (23)
目录
第三章椭偏仪测量不同厚度PtSe2的光学性质 (24)
第一节PtSe2薄膜的制备和光学表征 (24)
3.1.1 样品制备 (24)
3.1.2 光学表征 (25)
第二节椭偏仪测量PtSe2薄膜的光学常数 (31)
第三节实验结果的讨论 (40)
第四节本章小结 (40)
第四章总结与展望 (42)
不忘初心作文第一节总结 (42)
第二节展望 (42)
曹全碑隶书
驴肉火烧的做法参考文献 (44)
致谢 (50)
个人简历 (52)
在学期间发表的学术论文及研究成果 (52)
