在半导体-金属相变温度附近氧化钒薄膜光学性质的异常变动

Abnormal variation of optical properties of vanadium oxide thin film at semiconductor-metal transition

在可见光—近红外波段的不同波长下,测量了半导体-金属相变过程中氧化钒薄膜样品的反射率和透射率.在薄膜相变过程中,不同波段的反射率曲线和透射率曲线表现出不同的变化趋势.利用非相干光在薄膜中的多级反射-透射模型,计算了相变过程中不同波长下氧化钒薄膜的折射率n和消光系数k随温度的变化.结果表明,在相变温度附近氧化钒薄膜光学性质的异常变动,其原因既有薄膜的折射率和消光系数随波长的变化趋势不同,也有在吸收性薄膜中存在探测光多次反射和透射的累加效应.

The optical properties of vanadium oxide thin film are measured at semiconductor-metal transition, including reflectance and transmittance results at different wavelengths which show different trends during the phase transition. With a multi-level reflection-transmission model of incoherent light, we calculate the values of refractive index n and extinction coefficient k at different wavelengths, and show that the abnormal optical properties result not only from the dependences of n and k on the wavelength, but also from multiple reflections in the absorbing film.