PDF(Pubmed)
Abstract：
This study delves into the effects of titanium (Ti) doping on the optical properties of vanadium dioxide (VO2), a material well known for its metal-to-insulator transition (MIT) near room temperature. By incorporating Ti into VO2\'s crystal lattice, we aim to uncover the resultant changes in its physical properties, crucial for enhancing its application in smart devices. Utilizing polarized infrared micro-spectroscopy, we examined TixV1-xO2 single crystals with varying Ti concentrations (x = 0.059, x = 0.082, and x = 0.187) across different crystal phases (the conductive rutile phase and insulating monoclinic phases M1 and M2) from the far-infrared to the visible spectral range. Our findings reveal that Ti doping significantly influences the phononic spectra, introducing absorption peaks not attributed to pure VO2 or TiO2. This is especially notable with polarization along the crystal growth axis, mainly in the x = 0.187 sample. Furthermore, we demonstrate that the electronic contribution to optical conductivity in the metallic phase exhibits strong anisotropy, higher along the c axis than the a-b plane. This anisotropy, coupled with the progressive broadening of the zone center infrared active phonon modes with increasing doping, highlights the complex interplay between structural and electronic dynamics in doped VO2. Our results underscore the potential of Ti doping in fine-tuning VO2\'s electronic and thermochromic properties, paving the way for its enhanced application in optoelectronic devices and technologies.
摘要：
研究了钛(Ti)掺杂对二氧化钒(VO2)光学性能的影响,一种以接近室温的金属到绝缘体转变(MIT)而闻名的材料。通过将Ti掺入到VO2的晶格中，我们的目标是揭示其物理性质的变化，对于增强其在智能设备中的应用至关重要。利用偏振红外显微光谱，我们检查了从远红外到可见光谱范围的不同晶相（导电金红石相和绝缘单斜相M1和M2）中不同Ti浓度（x=0.059，x=0.082和x=0.187）的TixV1-xO2单晶。我们的发现表明，Ti掺杂显着影响声子光谱，引入不归因于纯VO2或TiO2的吸收峰。这在沿晶体生长轴的极化中尤其值得注意，主要在x=0.187样本中。此外，我们证明了电子对金属相中的光学电导率的贡献表现出强烈的各向异性，沿c轴高于a-b平面。这种各向异性，加上随着掺杂的增加，区域中心红外有源声子模式逐渐变宽，强调了掺杂VO2中结构动力学和电子动力学之间复杂的相互作用。我们的结果强调了Ti掺杂在微调VO2的电子和热致变色性能中的潜力，为其在光电设备和技术中的增强应用铺平了道路。
