MICROSCOPIC OBSERVATION OF THE GRAIN STRUCTURES OF ZNO BY PHOTOELECTROCHEMICAL ETCHING TECHNIQUE

The grain structures of polycrystalline undoped and Bi2O3 doped ZnO el ectrodes were investigated by photoelectrochemical etching technique. The photoelectrochemical etching of ZnO electrodes produces unique sur face morphologies on their surface depending on the crystallographic o rientations. The grain boundaries of an undoped ZnO are selectively di ssolved by the photoelectrochemical etching. Those of a Bi2O3 doped Zn O, on the other hand, are left undissolved. So that a direct observati on by TEM and a measurement of the chemical composition of those grain boundaries as isolated specimens could be carried out.