Abstract

In twisted bilayer graphene (tBLG), the electronic and optical properties show interesting dependence on the interlayer rotation angle(θ) with promising device applications [1,2]. The presence of the van Hove singularities in the density of states leads to an enhancement of the optical absorption at energies that depends on the rotation angle [2]. In single layer graphene, it has been shown that after excitation with a femtosecond pulse the excited carriers forms a quasi-equilibrium population at temperatures well above the lattice temperature that leads to thermal like emission, i.e. hot luminescence [3]. Here, we report on hot luminescence measurements with femtosecond laser pulse excitation on tBLG that shows an enhancement of the light emission as the excitation wavelength is tuned to a van Hove singularity resonance energy.

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