Harmonic Extraction in Graphene: Monte Carlo Analysis of the Substrate Influence

Graphene on different substrates, such as SiO2, h-BN and Al2O3, has been subjected to oscillatory electric fields to analyse the response of the carriers in order to explore the generation of terahertz radiation by means of high-order harmonic extraction. The properties of the ensemble Monte Carlo simulator employed for such study have allowed us to evaluate the high-order harmonic intensity and the spectral density of velocity fluctuations under different amplitudes of the periodic electric field, proving that strong field conditions are preferable for the established goal. Furthermore, by comparison of both harmonic intensity and noise level, the threshold bandwidth for harmonic extraction has been determined. The results have shown that graphene on h-BN presents the best featuring of the cases under analysis and that in comparison to III-V semiconductors, it is a very good option for high-order harmonic extraction under AC electric fields with large amplitudes.