▎ 摘　　要

We have studied numerically the statistics for electronic states (level spacings and participation ratios) from disordered graphene dots of finite size, described by the aspect ratio W/L and various geometries, corresponding to finite chiral or achiral carbon nanotubes. Quantum chaotic Wigner energy level-spacing distribution is found for weak disorder, even infinitesimally small disorder for wide and short tight-binding samples (W/L > 1), while for strong disorder, Anderson localization with Poisson level-statistics always sets in. Although pure graphene near the Dirac point corresponds to integrable ballistic statistics diffusive chaotic behavior seems more common for realistic (weakly disordered) finite samples.