Potential of graphene/AlGaN/GaN heterostructures to study the drag and two-stream instability effects

Graphene/AlGaN/GaN heterostructures are proposed to investigate the drag and two-stream instability effects. In this study, graphene grown by chemical vapor deposition was transferred from copper onto the top of a “standard” AlGaN/GaN wafer, forming a heterostructure with two conducting layers separated by an AlGaN barrier layer. Contacts fabricated to the two-dimensional electron gas and graphene allowed us to study the drag current induced in graphene by passing the drive current through the two-dimensional electron gas. At low temperatures, the graphene drag current exhibited quantum oscillations as a function of the drive voltage. As temperature increases, quantum oscillations disappear, and the magnitude of the drag current increases. Graphene/AlGaN/GaN heterostructures are a promising platform for studying drag and two-stream instability effects, especially if the AlGaN barrier layer thickness can be reduced to a few nanometers.