Abstract
我們應用濺鍍系統成長了不同厚度的Nb薄膜，並對其物性作了詳細的量測。我們發現許多這些薄膜的物性，例如殘餘電阻率、Tc隨薄膜厚度的變化、Hc2、I-V curve的行為、有效相干長度變化的趨勢等，均顯示厚度大於80nm與厚度小於80nm之薄膜有相當差異的行為。我們認為這代表Nb的性質在厚度80nm以上是為三維系統，而在80nm以下較接近二維系統。We have carried out a systematic study on the effect of filmthickness to the physical properties of superconducting Nb thinfilms prepared by sputtering technique. We observed thatseveral properties such as the residual conductivity,superconducting transition temperature TC, upper critical fieldHC2, I-V characteristics, and the effective coherence length,are characteristically different for films thicker or thinnerthan 80 nm. Detailed analysis of the data suggest that theobserved behavior are related to the dimensional crossover ofthe studied films. The characteristic of the films that isthicker than 80 nmis 3-dimensional, while those with thicknessless than 80nm behave more like 2-dimensional system.