AbstractPhotoluminescence (PL) was circumstantially measured for ZnO single crystals with polar and non‐polar faces. PL spectra of ZnO single crystals depended on the sector and polarity of ZnO single crystals. Emissions due to excitons from c ‐plane substrates sliced from the +c sector were strong, and FWHMs of the emissions were smaller than those from substrates sliced from the –c sector. An emission due to neutral‐donor‐bound exicitons (D0X) at 3.361 eV was dominantly observed on all surfaces of ZnO single crystals, and an emission due to ionized‐donor‐bound excitons (D+X) around 3.366 eV was observed on the O‐face but not on the Zn‐face at 4.2 K. It is thought that surface state densities due to oxygen caused this difference in PL emission for polarity of ZnO. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)