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On-chip demagnetization refrigeration has recently emerged as a powerful tool for reaching microkelvin electron temperatures in nanoscale structures. The relative importance of cooling on-chip and off-chip components and the thermal subsystem dynamics are yet to be analyzed. We study a Coulomb blockade thermometer with on-chip copper refrigerant both experimentally and numerically, showing that dynamics in this device are captured by a first-principles model. Our work shows how to simulate thermal dynamics in devices down to microkelvin temperatures, and outlines a recipe for a low-investment platform for quantum technologies and fundamental nanoscience in this novel temperature range., Comment: 11 pages, 10 figures

Since the introduction of bolometers more than a century ago, they have been applied in a broad spectrum of contexts ranging from security and the construction industry to particle physics and astronomy. However, emerging technologies and missions call for faster bolometers with lower noise. Here, we demonstrate a nanobolometer that exhibits roughly an order of magnitude lower noise equivalent power, $20\textrm{ zW}/\sqrt{\textrm{Hz}}$, than previously reported for any bolometer. Importantly, it is more than an order of magnitude faster than other low-noise bolometers, with a time constant of 30 $\mu$s at $60\textrm{ zW}/\sqrt{\textrm{Hz}}$. These results suggest a calorimetric energy resolution of $0.3\textrm{ zJ}=h\times 0.4$ THz with a time constant of 30 $\mu$s. Thus the introduced nanobolometer is a promising candidate for future applications requiring extreme precision and speed such as those in astronomy and terahertz photon counting.

NEWRAD 2017, Miraikan Hall, in Odaiba, Tokyo 13 - 16 June, 2017, We have designed, manufactured, modelled and characterized a new type of predictable quantum efficient detector (PQED) based on n-type induced junction photodiodes. The photodiodes utilize an Al2O3 layer grown on top of n-type silicon substrate using atomic layer deposition. Two sets of photodiodes with varying doping concentrations were fabricated. For both sets, the modelled and measured responsivities were congruent within the measurement and modelling uncertainties of around 100 ppm. Thus, the new design is a good alternative to the existing PQEDs, where p-type silicon and a thermally grown SiO2 layer are used. A novel experimental method was developed to obtain values of the 3D model parameters giving increased credibility to the PQED as a primary standard, The research leading to these results has received funding from the European Metrology Research Programme (EMRP) project SIB57 “New Primary Standards and Traceability for Radiometry”. The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union.

We report the cooling of electrons in nanoelectronic Coulomb blockade thermometers below 4 mK. Above 7 mK the devices are in good thermal contact with the environment, well isolated from electrical noise, and not susceptible to self-heating. This is attributed to an optimised design that incorporates cooling fins with a high electron-phonon coupling and on-chip electronic filters, combined with a low-noise electronic measurement setup. Below 7 mK the electron temperature is seen to diverge from the ambient temperature. By immersing a Coulomb Blockade Thermometer in the 3He/4He refrigerant of a dilution refrigerator, we measure a lowest electron temperature of 3.7 mK., Comment: 11 pages, 4 figures. (Fixed fitted saturation T_e on p9)

We demonstrate significant modification of the electron-phonon energy loss rate in a many-valley semiconductor system due to lattice mismatch induced strain. We show that the thermal conductance from the electron system to the phonon bath in strained n + Si, at phonon temperatures between 200 mK and 450 mK, is more than an order of magnitude lower than that for a similar unstrained sample.

Atomic layer deposition of thin TiN layer inside the porous silicon electrodes improves conductivity and passivates surface of porous silicon. This improves performance of porous silicon based supercapacitors.

Atomic layer deposition of thin TiN layer inside the porous silicon electrodes improves conductivity and passivates surface of porous silicon. This improves capacitance and stability of porous silicon based supercapacitors.