Design, Preparation And Electrical-explosion Characterization Of Schottky-junction-based Al/CuO Initiators

Al/CuO reactive multilayer films are a new kind of energetic material, which consist of alternatively stacked Al thin films and CuO thin films. These stacked films can react exothermically and release reacted heat under electricity stimulation. According to solid state electronics theory, a Schottky junction forms when a metallic Al thin film contacts a semiconducting CuO thin film because of the different work functions. Therefore, Al/CuO reactive multilayer films have the critical breakdown voltage in electrical stimulation. This paper is to evaluate the possibility of applying Al/CuO reactive multilayer films for the ignition and initiation of energetic materials, based on its two marked characteristics. The particular research content and conclusions are as follows:(1) CuO film and Ni doped Cu0.95Ni0.05O film were prepared using magnetron sputtering and micro fabrication techniques. Their semiconductor properties, microstructure, chemical component and so on were characterized using various characterization methods. Then on this basis, the preparation processing conditions were optimized. In addition, it is demonstrated that CuO film and Cu0.95Ni0.05O film are P type semiconductor thin film materials, and the conductivity of Cu0.95Ni0.05O film is superior to CuO film.(2) Three types of Schottky-j unction-based Al/CuO initiators were designed, which were abbreviated to S-Al/CuO-Ⅰ, S-Al/CuO-Ⅱ and S-Al/CuO-Ⅲ. The electrical breakdown voltage, security, electrical-explosion induced plasma temperature and electrical-explosion induced energy transfer rules were investigated respectively for the three types of initiators. Results shown that they possess the same characteristics as follows:1) the breakdown voltage is characteristic of the junction material, and did not depend notably on the number and contact area of Schottky junctions; 2) initiator’s firing threshold, energy utilization ratio, plasma temperature rise time and duration are positively correlated with Schottky junction number; 3) electrical-explosion induced energy transfer are composed of the electrical breakdown of Schottky junction, electrical-explosion induced plasma and sputtering of reaction products.(3) S-Al/CuO-I exhibited multiple firing characteristic. After the first electrical explosion, the electro-explosive region was still conductive, allowing for another electrical explosion. The firing could be repeated until the electro-explosive region was totally broken. It can be considered that the Schottky junction-based Al/CuO energetic initiator could withstand hard electromagnetic interference.The S-Al/CuO-Ⅲ is able to withstand lA/5min no-fire, and it is of great safety.The research results show that Al/CuO reactive multilayer films are novel energetic functional materials which have wide applications in initiators and pyrotechnics. However, further work is required. The design must be optimized and great attention must be paid to research the initiation of insensitive explosives.