Hyperdoping Si with chalcogens is a topic of great interest due to the strong sub-bandgap absorption exhibited by the resulting material, which can be exploited to develop broadband room-temperature infrared photodetectors using fully Si-compatible technology. Here, we report on the critical behavior of the impurity-driven insulator-to-metal transition in Te-hyperdoped Si layers fabricated via ion implantation followed by nanosecond pulsed-laser melting. Electrical transport measurements reveal an insulator-to-metal transition, which is also confirmed and understood by density functional theory calculations. We demonstrate that the metallic phase is governed by a power law dependence of the conductivity at temperatures below 25 K, whereas the conductivity in the insulating phase is well described by a variable-range hopping mechanism with a Coulomb gap at temperatures in the range of 2-50 K. These results show that the electron wave-function in the vicinity of the transition is strongly affected by the disorder and the electron-electron interaction.
@article{arxiv.2004.02710,
title = {Critical behavior of the insulator-to-metal transition in Te-hyperdoped Si},
author = {Mao Wang and A. Debernardi and Wenxu Zhang and Chi Xu and Ye Yuan and Yufang Xie and Y. Berencén and S. Prucnal and M. Helm and Shengqiang Zhou},
journal= {arXiv preprint arXiv:2004.02710},
year = {2020}
}