Impact of ZnO Cap Layer on the Performance of MgZnO/CdZnO Heterostructure With Y<inline-formula> <tex-math notation="LaTeX">$_{\text{2}}$</tex-math> </inline-formula>O<inline-formula> <tex-math notation="LaTeX">$_{\text{3}}$</tex-math> </inline-formula> Spacer Layer

Abstract

In this work, we report the impact of the ZnO cap layer on mobility (<inline-formula> <tex-math notation="LaTeX">$\mu$</tex-math> </inline-formula>), sheet carrier density (<italic>n</italic> <inline-formula> <tex-math notation="LaTeX">$_{\textit{s}}$</tex-math> </inline-formula>), and conductance (<italic>n</italic> <inline-formula> <tex-math notation="LaTeX">$_{\textit{s}}$</tex-math> </inline-formula> <inline-formula> <tex-math notation="LaTeX">$\times$</tex-math> </inline-formula> <inline-formula> <tex-math notation="LaTeX">$\mu$</tex-math> </inline-formula>) of dual ion beam sputtering (DIBS) grown MgZnO/CdZnO (MCO) heterostructure with and without Y<inline-formula> <tex-math notation="LaTeX">$_{\text{2}}$</tex-math> </inline-formula>O<inline-formula> <tex-math notation="LaTeX">$_{\text{3}}$</tex-math> </inline-formula> spacer layer. Hall measurements demonstrate that the addition of a 30-nm ZnO cap layer results in an enhancement of <inline-formula> <tex-math notation="LaTeX">$\mu$</tex-math> </inline-formula> by about 2.3<inline-formula> <tex-math notation="LaTeX">$\times$</tex-math> </inline-formula> 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. IEEE