Nuclear techniques for studying thin films

Abstract

It is well known that “Thin films” exhibit exotic properties, and a layer of thin film can bring dramatic changes in mechanical, electrical, magnetic, and optical properties of bulk material. It is also known that the characteristic properties of a thin film depend on its composition, surface-to-volume ratio, and morphology developed during growth. However, development of thin films with required characteristics and production in large scale has still remained a challenge. A comprehensive understanding of the process of development and properties, which means connecting the microstructures with macroscopic properties of thin films, is the basic requirement for exploiting the application potential of thin films in full extent. This requires development of films under controlled condition, monitoring during film growth, and precise in situ measurement of thin film parameters during film growth and finally after production. Among available methods for measurement of thin film parameters, nuclear techniques are those in which exotic properties of atomic nuclei are exploited for measurement purpose. Thin films are sometimes a few atomic layers, measurements based on nuclear techniques where every nucleus participates are expected to give better signal-to-noise ratio. It is to be noted that most of the nuclear techniques are nonevasive and very selective and highly sensitive. This article contains a general description of these nuclear techniques based on ion beam analysis, exotic properties of nuclei and their interactions. The article also describes such techniques and their advantages and evolution path that made thin film studies using nuclear techniques possible.