▎ 摘　　要

We analyze the statistical characteristics of quasinonequilibrium two-dimensional electron-hole plasmas in graphene layers (GLs) and graphene bilayers (GBLs) and evaluate their heat capacity. The GL heat capacity of the weakly pumped intrinsic or weakly doped GLs normalized by the Boltzmann constant is equal to c(GL) similar or equal to 6.58. With varying carrier temperature the intrinsic GBL carrier heat capacity c(GBL) changes from c(GBL)similar or equal to 2.37 at T less than or similar to 300 K to c(GBL) similar or equal to 6.58 at elevated temperatures. These values are markedly different from the heat capacity of classical two-dimensional carriers with c = 1. The obtained results can be useful for the optimization of different GL- and GBL-based high-speed devices.