Jun XU

Nanjing University, China

Title: Doping in Nano-scaled Si Dots

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Biography

Jun Xu received Ph. D in Department of Physics, Nanjing University and joined National laboratory of Solid State Microstructures, Nanjing University in 1995. Now, Jun Xu is a full professor in school of electronic science and engineering, Nanjing University and PI of Nano-semiconductors and nano-devices group in collaborative innovation centre of advanced microstructures. He has been engaged in research on silicon-based nanocrystalline materials, optical and transport properties in low-dimensional semiconductors and nano-devices. He has published more than 300 peer-reviewed papers and received many awards. 

Abstract

Doping is a powerful technique to control the electronic and optical properties of semiconductors. Due to the continuously developing Si technology, the feature size of the device becomes smaller and smaller, now is in the nano-scaled region. However, doping in nano-scale is a quite complicated topic and it is current an interesting research subject. Here, we fabricated P and/or B doped Si nanocrystals (Si NCs)-based multilayers and studied the doping effect both theoretically and experimentally. We used ESR and Hall measurements to investigate the dopant location and the changes in conductivity. Our observation manifested that part of dopants can occupy the inner sites of Si dots substitutionally,  but most of dopants occupy the surface or sub-surface sites. It was also found that the light emission intensity from ultra-small Si dots can be enhanced by suitable P doping which can be attributed to the reduced surface defect states. More interestingly, a sub-band light emission has been observed which can be enhanced by changing the doping levels. The possible mechanism will be briefly discussed. This work is partly supported by NSFC (No. 91621005).