Non-invasive bioinert room-temperature quantum sensor from silicon carbide qubits

Room-temperature shallow defect spin qubits acting as a quantum sensor with favourable properties towards the biological environment are sought after, with promising impacts on bioimaging, radical detection and nanoscale nuclear spin sensing. Here we show that alkene-terminated silicon carbide hosting divacancy qubits located a few nanometres below the surface leads to a stable operation with superior sensitivity in which the host is a bioinert semiconductor with existing wafer-scale chip technology. The read-out of the qubit occurs at near-infrared wavelengths, which exhibit a minimum absorption by the organic molecules or water. We show that the divacancy qubit can realize multiple quantum sensor schemes under ambient conditions in which the suggested surface termination can be readily tailored towards the desired application. The combination of the paramount host, surface functionalization and qubit properties may significantly advance room-temperature quantum sensing, as well as provide a platform for quantum simulation and optoelectronic devices.