Tunable excitons in bilayer graphene

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Science  17 Nov 2017:
Vol. 358, Issue 6365, pp. 907-910
DOI: 10.1126/science.aam9175

Pairing up electrons and holes in bilayer graphene

Excitons—bound pairs of electron and holes in solids—can be harnessed for optoelectronic applications. Being able to tune the exciton energy would bring functional flexibility to such devices. Although tunable excitons have been predicted to form in bilayer graphene, observing them experimentally has been difficult. Ju et al. used high-quality bilayer graphene samples sandwiched between layers of hexagonal boron nitride to observe excitons in this material. Exciton energy was tuned across a large range by controlling the gate voltages.

Science, this issue p. 907