Positron lifetime study on semiconductor thin films

Positron lifetime studies on various semiconductor thin films, e.g. CuInSe₂, amorphous Si, ion implanted Si, SiC, etc. have been done with a pulsed slow positron beam at the Electrotechnical Laboratory. The results gives us valuable information on not only small vacancy type defects but also large vacancy clusters or voids in thin films. Furthermore, combination of positron lifetime and Doppler broadening measurements gives us more detailed information on the defects. To discuss these features, we present experimental results of CuInSe₂, hydrogenated amorphous Si (a-Si:H), and fluorine-ion implanted Si. Moreover, we report significant positron re-emission from 3C-SiC and GaN films measured by the positron lifetime apparatus.