Characterization of low-resistance ohmic contacts to a two-dimensional electron gas in a GaAs/AlGaAs heterostructure

摘要: The study of electron transport in low-dimensional systems is importance, not only from a fundamental point view, but also for future electronic and spintronic devices. In this context heterostructures containing two-dimensional gas (2DEG) are key technology. particular GaAs/AlGaAs heterostructures, with 2DEG at typically 100 nm below the surface, widely studied. order to explore such systems, low-resistance ohmic contacts required that connect macroscopic measurement leads surface. Here we report on designing measuring dedicated device unraveling various resistance contributions contacts, which include pristine series resistance, under contact, contact itself, influence pressing bonding wire onto contact. We here recipe very low values remain 10 Ω annealing times between 20 350 s, hence providing flexibility use method materials different depths. type heating, temperature ramp rate forming used found strongly process quality resulting contacts.