Study of 2DEGs at the interface of Hybrid MBE Grown SrNbO₃ on BaSnO₃

Over a decade, two-dimensional electron gases (2DEGs) in complex oxide interfaces have emerged as an option for high speed electronics. Modulation doping is an popular technique to produce high carrier-concentration 2DEGs by separating the carriers from the donors at an interface to improve mobility. The search for good donors has led to the complex oxide perovskite, SrNbO₃ (SNO), which has one free electron to donate. Moreover, BaSnO₃ (BSO) is well known for its high mobility due to an availability of unoccupied 5s bands in Sn. Hybrid molecular beam epitaxy (hMBE) has been used to grow SNO film on as prepared BSO film on different substrates with Nb supplied using TDTBN precursor and Sr supplied as an elemental source. In situ RHEED is used to compare the crystal quality and stoichiometry of the sample right after growth and after cooling down. In vacuo XPS is used to quantify the oxidation state of Nb and band alignment at the interface. These studies help to understand the high-quality SNO film growth using hMBE approach and quantify the carrier concentration and mobility in SNO/BSO interface. In the future, this study could open the door for long awaited search of promising alternatives for traditional semiconductor in high mobility devices.