X-ray studies of materials modified by high energy ion beams

点击翻译按钮获取中文摘要

When an energetic, heavy ion hits a solid target such as silicon or glass, it creates a long and narrow cylinder of damage, the so-called ion track. It is believed by many, and since many years, that the ion track melts, if ever so briefly (for less than a nano-second). However, no convincing proof exist and that is a pity, because these ion impacts happen more often than most would think (ion beam processing, nuclear waste storage, cosmic ray interference). I am planning to provide exactly such evidence, and will explain how in my proposal. The planned experiment will take place in amorphous silicon, and I plan to discover other fundamental properties of this important material as well. For example, we have recently shown that a-Si is "hyperuniform", a property it shares with cristalline (non-amorphous) materials but not with liquids and we plan to study its close cousin, amorphous germanium, because we expect it to be even more "hyperuniform". In the course of the hyperuniformity measurements, we discovered a small but significant peak in the diffraction pattern of amorphous silicon that should not be there, and I describe in the proposal how we are going to find out what causes it.One important application of disordered materials is for the conversion of light to electricity. In this proposal, I present two projects to improve devices that do this type of conversion: one is aimed to improve the response time of a new type of (highly sensitive) infra-red detector and another aims to improve the conversion efficiency of plastic solar cells.