Speaker: Luyan Sun, Laboratory for Physical Sciences, University of Maryland
Abstract: The background charges in Si/SiO2 systems may be sources of decoherence for Si qubits. Understanding the charge environment is thus important for potential quantum information processing in Si. In this talk I will show that at low temperature an Al-AlOx-Al single electron transistor (SET) acting as the gate of a narrow (~ 100 nm) metal-oxide-semiconductor field-effect transistor can induce a self-aligned and vertically-coupled Si SET at the Si/SiO2 interface. Then I will demonstrate the detection of a single charge defect, either a single charge trap at the Si/SiO2 interface or a single donor in the Si substrate, using such an SET sandwich architecture. In conclusion, I will briefly discuss the high mobility two-dimensional electron systems fabricated in our group on hydrogen-terminated silicon (111) surfaces and our new approach to detecting donor electrons in silicon using a scanned probe based on a quartz tuning fork.