Transition-edge sensor (TES) microcalorimeters are promising for application in the field of quantum information and quantum computation thanks to their outstanding single photon detection capabilities. Good energy resolution and photon number discrimination at visible and near-infrared wavelengths make them extensively used as single photon detectors. In this work we report details on the fabrication of Pd/Ti TESs deposited by e-beam evaporation on silicon nitride substrates. We use Pd as alternative to Au layer thanks to its stronger influence on the Ti layer, that allows to obtain the same temperature reduction with thinner layers. The transition temperatures Tcof the devices range from 83 to 110 mK with a transition width DeltaTc=0.5 mK. Thermal and electric characteristics of Pd/Ti TESs at different temperatures and its capability as single photon sensor are reported.
Transition-edge sensor (TES) microcalorimeters are extensively used as single photon detectors from infrared to x-ray. Their good energy resolution and photon number resolving capability at visible and near-infrared wavelengths make them powerful tools for quantum information and quantum computation. In this work we report details on the fabrication of Ti/Pd TESs deposited by e-beam evaporation on silicon nitride substrates. By the proximity effect between Ti and Pd, the Ti critical temperature was tuned down to 100 mK, usual working temperature for these devices. Sharp transition of two-three mK and reproducible Tc were obtained. The Pd material can be a valid alternative to widely used Au proximity material thanks to its stronger influence on the Ti layer, that allows to obtain the same temperature reduction with thinner layers. Thermal and electrical characteristics of Ti/Au and Ti/Pd bilayers are compared in view of single photon detection.
We demonstrate high-fidelity single qubit control in a natural Si-MOS quantum dot fabricated in an industrial 300 mm wafer process on a silicon on insulator (SOI) wafer using electron spin resonance. A relatively high optimal Rabi frequency of 5 MHz is achieved, dynamically decoupling the electron spin from its 29-Si environment. Tracking the qubit frequency reduces the impact of low frequency noise in the qubit frequency and improves the
TRabi from 7 to 11
μs at a Rabi frequency of 5 MHz, resulting in Q-factors exceeding 50. Randomized benchmarking returns an average single gate control fidelity of 99.5
± 0.3%. As a result of pulse-area calibration, this fidelity is limited by the Rabi Q-factor. These results show that a fast Rabi frequency, low charge noise, and a feedback protocol enable high fidelity in these Si-MOS devices, despite the low-frequency magnetic noise.