Urbieta Quiroga, Ana IreneFernández Sánchez, PalomaPiqueras De Noriega, Francisco JavierSekiguchi, T.2023-06-202023-06-202001-070268-124210.1088/0268-1242/16/7/311https://hdl.handle.net/20.500.14352/59124© 2001 IOP Publishing Ltd. This work was supported by MCYT –DGI (ProjectMAT2000-2119). Thanks are due to Professor N Sakagami (Akita National College of Technology, Japan) and Professor S Miyashita (Toyama Medical and Pharmaceutical University, Japan) for their contribution to crystal preparation.Bulk ZnO single crystals grown by the hydrothermal and flux methods have been characterized by scanning tunnelling spectroscopy performed in the different crystalline faces. Normalized differential conductance has been found to depend on the face considered. Polar O-terminated surfaces show an intrinsic conduction behaviour and surface bandgap in the range 0.4-0.8 eV, which depends on the position probed. The Zn polar surfaces show mainly n-type conduction. The non-polar m regions present either intrinsic or p-type behaviour. The differences observed are attributed to the nature of impurities and defects appearing in the polar and non-polar surfaces during crystal growth.engjournal articlehttp://dx.doi.org/10.1088/0268-1242/16/7/311http://iopscience.iop.orgrestricted access538.9Tunneling SpectroscopyZinc-OxideElectronic-StructureSi(111)2x1 SurfaceMicroscopyCeramicsFísica de materiales