Atomistic analysis of band-to-band tunnelling in direct-gap $\mathrm{Ge}_{1-X}\mathrm{Sn}_{x}$ group-IV alloys
| Autor: | Mathieu Luisier, Eoin P. O'Reilly, Michael D. Dunne, Christopher A. Broderick |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
0303 health sciences
Materials science Condensed matter physics business.industry Group (mathematics) Band gap Alloy Material system 02 engineering and technology engineering.material 021001 nanoscience & nanotechnology Kinetic energy 03 medical and health sciences engineering Optoelectronics Direct and indirect band gaps Edge states 0210 nano-technology business Quantum tunnelling 030304 developmental biology |
| Zdroj: | 2020 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD). |
| DOI: | 10.1109/nusod49422.2020.9217765 |
| Popis: | The emergence of a direct band gap in $\mathrm{Ge}_{1-x}\mathrm{Sn}_{x}$ alloys has stimulated interest in developing $\mathrm{Ge}_{1-x}\mathrm{Sn}_{x}$ alloys and nanostructures for applications in Si-compatible electronic and photonic devices. The direct band gap of $\mathrm{Ge}_{1-x}\mathrm{Sn}_{x}$ , combined with the strong band gap reduction associated with Sn incorporation, makes $\mathrm{Ge}_{1-x}\mathrm{Sn}_{x}$ a promising material system for the development of Si-compatible tunnel field-effect transistors (TFETs) due to an expected strong increase in band-to-band tunnelling (BTBT). Based on a semi-empirical tight-binding model, we establish quantum kinetic BTBT current calculations for atomistic $\mathrm{Ge}_{1-x}\mathrm{Sn}_{x}$ alloy supercells. Recent analysis suggests that $\mathrm{Ge}_{1-x}\mathrm{Sn}_{x}$ possesses hybridised conduction band edge states for $x \lesssim 10{\%}$ . We demonstrate that Sn-induced band mixing opens up a pathway for direct BTBT in ordered alloy supercells, strongly enhancing BTBT current compared to Ge. The framework we establish allows for quantitative prediction of the properties and performance of $\mathrm{Ge}_{1-x}\mathrm{Sn}_{x}$ -based TFETs. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|