Impact of ZnO Cap Layer on the Performance of MgZnO/CdZnO Heterostructure With YO Spacer Layer

In this work, we report the impact of the ZnO cap layer on mobility (
$\mu $
), sheet carrier density (
${n} _{s}$
), and conductance (
${n} _{s} \times \mu $
) of dual ion beam sputtering (DIBS) grown MgZnO/CdZnO (MCO) heterostructure with and without
$\text{Y}_{{2}}\text{O}_{{3}}$
spacer layer. Hall measurements demonstrate that the addition of a 30-nm ZnO cap layer results in an enhancement of
$\mu $
by about
$2.3\times $
compared to that for the uncapped MCO heterostructure with a spacer layer. The results presented are significant for the realization of cost-effective and large area MCO-based heterostructure field-effect transistor (HFET) for sensor, microwave, and power devices.