title: Single-chip electron spin resonance detectors operating at 50GHz, 92GHz, and 146GHz.
abstract: We report on the design and characterization of single-chip electron spin resonance (ESR) detectors operating at 50GHz, 92GHz, and 146GHz. The core of the single-chip ESR detectors is an integrated LC-oscillator, formed by a single turn aluminum planar coil, a metal-oxide-metal capacitor, and two metal-oxide semiconductor field effect transistors used as negative resistance network. On the same chip, a second, nominally identical, LC-oscillator together with a mixer and an output buffer are also integrated. Thanks to the slightly asymmetric capacitance of the mixer inputs, a signal at a few hundreds of MHz is obtained at the output of the mixer. The mixer is used for frequency down-conversion, with the aim to obtain an output signal at a frequency easily manageable off-chip. The coil diameters are 120μm, 70μm, and 45μm for the U-band, W-band, and the D-band oscillators, respectively. The experimental frequency noises at 100kHz offset from the carrier are 90Hz/Hz1/2, 300Hz/Hz1/2, and 700Hz/Hz1/2at 300K, respectively. The ESR spectra are obtained by measuring the frequency variations of the single-chip oscillators as a function of the applied magnetic field. The experimental spin sensitivities, as measured with a sample of α,γ-bisdiphenylene-β-phenylallyl (BDPA)/benzene complex, are 1×108spins/Hz1/2, 4×107spins/Hz1/2, 2×107spins/Hz1/2at 300K, respectively. We also show the possibility to perform experiments up to 360GHz by means of the higher harmonics in the microwave field produced by the integrated single-chip LC-oscillators.
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.
authors.forename: Alessandro V
authors.initials: AV
authors.lastname: Matheoud
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Gualco
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.
authors.forename: Minki
authors.initials: M
authors.lastname: Jeong
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.
authors.forename: Ivica
authors.initials: I
authors.lastname: Zivkovic
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Brugger
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.
authors.forename: Henrik M
authors.initials: HM
authors.lastname: Rønnow
authors.affiliation: University of Ulm, D-89081 Ulm, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Anders
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland. Electronic address: giovanni.boero@epfl.ch.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Boero
keywords: CMOS; ESR; LC-oscillator