We investigated the Fermi-energy ($E_{\mathrm{F}}$) dependence of the photoluminescence (PL) of monolayer graphene. The steady-state PL spectra for $2|E_{\mathrm{F}}|=0.80$, 1.04, and 1.22 eV (the origin of electron energy was set at the Dirac point) showed a high-energy shift of the spectral edge (Fermi edge) with an increase in $2|E_{\mathrm{F}}|$. The PL decay curve at a PL photon energy ($E_{\mathrm{PL}}$) of 1.10 eV was observed in the $E_{\mathrm{F}}$ range of +0.30 to −0.61 eV. It was found that the $E_{\mathrm{F}}$ dependence of the maximum intensity in each PL decay curve had the largest value at $E_{\mathrm{F}}=-0.55\pm 0.06\mathrm{eV}$, and $E_{\mathrm{PL}}\sim 2\left|E_{\mathrm{F}}\right|$. The observed results are discussed in terms of the Fermi edge singularity due to many-body electron-hole interactions.

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• Excitons
• Graphene
• Femtosecond laser spectroscopy
• Photoluminescence
• Time-resolved photoluminescence