An inkjet printed, biocompatible, heterostructure photodetector is described that was constructed using inks of photo-active molybdenum disulfide (MoS₂) and electrically conducting graphene which facilitated charge collection of the photocarriers. The importance of such devices stems from their potential utility in age-related-macular degeneration, which is a condition where the photosensitive retinal tissue degrades with aging, eventually compromising vision. The absence of effective therapeutic remedies for patients with this disorder has motivated the development of such devices to restore some degree of visual function. Inkjet printed, flexible prosthetic devices offer design simplicity where additive manufacturing can enable large format, low-cost arrays. The biocompatible inkjet printed two-dimensional heterojunction devices were photoresponsive to broadband incoming radiation in the visible regime, and the photocurrent I_ph scaled proportionally with the incident light intensity, exhibiting a photoresponsivity R ~ 0.30 A/W. This is 10³ times higher compared to prior reports, and detectivity D was calculated to be ~3.6 × 10¹⁰ Jones. Strain-dependent measurements were also conducted with bending, indicating the feasibility of such devices printed on flexible substrates. Drop cast and printed CT-MoS₂ inks were characterized using techniques, such as Raman spectroscopy, photoluminescence measurements and scanning electron microscopy. Both mouse embryonic fibroblast and human esophageal fibroblast were used for the biocompatibility analysis for inks drop cast on two types of flexible substrates, polyethylene terephthalate and polyimide. The biocompatibility of inks formed using two-dimensional graphene and MoS₂ on polyimide substrates was extremely high, in excess of 98% for mouse embryonic fibroblast.

Macroscopic resonant tunneling between the two lowest lying states of a bistable rf SQUID is used to characterize noise in a flux qubit. Measurements of the incoherent decay rate as a function of flux bias revealed a Gaussian-shaped profile that is not peaked at the resonance point but is shifted to a bias at which the initial well is higher than the target well. The rms amplitude of the noise, which is proportional to the dephasing rate $1/{\tau }_{\phi }$, was observed to be weakly dependent on temperature below 70 mK. Analysis of these results indicates that the dominant source of low energy flux noise in this device is a quantum mechanical environment in thermal equilibrium.

A general method for directly measuring the low-frequency flux noise (below 10 Hz) in compound Josephson-junction superconducting flux qubits has been used to study a series of 85 devices of varying design. The variation in flux noise across sets of qubits with identical designs was observed to be small. However, the levels of flux noise systematically varied between qubit designs with strong dependence upon qubit wiring length and wiring width. Furthermore, qubits fabricated above a superconducting ground plane yielded lower noise than qubits without such a layer. These results support the hypothesis that local impurities in the vicinity of the qubit wiring are a key source of low-frequency flux noise in superconducting devices.