Impact of defect distribution on transport properties for Au/ZnO Schottky contacts formed with H2O2-treated unintentionally doped n-type ZnO epilayers

The Au/ZnO Schottky contacts fabricated using H2O2-treated unintentionally doped ZnO epilayers showed an abnormal behavior in their transport properties; i.e., the background carrier density-dependent trade-off relation between the barrier height and the ideality factor was observed. This result is attributed to the difference in carrier transport mechanisms for each sample fabricated using ZnO epilayers with different background carrier concentrations; namely, the observed trade-off relation originates from a result that the difference in the distribution of oxygen vacancies near the surface and depletion regions, which depends on the initial background carrier concentration of each sample, causes the different carrier transport mechanism.