Influence of ion-beam etching on the transport properties and the structural quality of microstructured zinc-oxide layers

We developed a wire pattern which is defined on zinc-oxide layers using photolithography and transfered into the layer using ion-beam etching. We investigated the transport behavior and the structural quality of the wire samples obtained. Ion-beam etching is a promising alternative to wet-chemical etching as higher aspect ratios may be achieved. A possible disadvantage is the structural damage of the layer due to ion implantation (gas or mask ions) as well as due to ion scattering processes deep inside the layer or substrate. The structured samples were investigated by Raman microscopy in back scattering geometry using a 633 nm, 532 nm and 325 nm laser excitation, respectively. This yields information about vibrational modes and possible lattice defects such as impurities or vacancies. In addition the surfaces of the samples were studied via AFM and SEM in order to examine the structural quality and to determine the geometric dimensions of the individual wires. Furthermore we performed magnetotransport measurements to study the electronic transport properties after the etching treatment, mainly to investigate the influence of the damaged region on the electronic properties.