Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userA Strained Silicon Cold Electron Bolometer using Schottky Contacts
319
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We describe optical characterisation of a Strained Silicon Cold Electron Bolometer (CEB), operating on a $350~mathrm{mK}$ stage, designed for absorption of millimetre-wave radiation. The silicon Cold Electron Bolometer utilises Schottky contacts between a superconductor and an n++ doped silicon island to detect changes in the temperature of the charge carriers in the silicon, due to variations in absorbed radiation. By using strained silicon as the absorber, we decrease the electron-phonon coupling in the device and increase the responsivity to incoming power. The strained silicon absorber is coupled to a planar aluminium twin-slot antenna designed to couple to $160~mathrm{GHz}$ and that serves as the superconducting contacts. From the measured optical responsivity and spectral response, we calculate a maximum optical efficiency of $50~%$ for radiation coupled into the device by the planar antenna and an overall noise equivalent power (NEP), referred to absorbed optical power, of $1.1 times 10^{-16}~mathrm{mbox{W Hz}^{-1/2}}$ when the detector is observing a $300~mathrm{K}$ source through a $4~mathrm{K}$ throughput limiting aperture. Even though this optical system is not optimised we measure a system noise equivalent temperature difference (NETD) of $6~mathrm{mbox{mK Hz}^{-1/2}}$. We measure the noise of the device using a cross-correlation of time stream data measured simultaneously with two junction field-effect transistor (JFET) amplifiers, with a base correlated noise level of $300~mathrm{mbox{pV Hz}^{-1/2}}$ and find that the total noise is consistent with a combination of photon noise, current shot noise and electron-phonon thermal noise.
rate research
Read More
We have measured a response to a black body radiation and noise of the cold-electron bolometers. The experimental results have been fitted by theoretical model with two heat-balance equations. The measured noise has been decomposed into several terms with the help of theory. It is demonstrated that the photon noise exceeds any other noise components, that allows us to conclude that the bolometers see the photon noise. Moreover, a peculiar shape of the noise dependence on the absorbed power originates completely from the photonic component according to the theory. In the additional experiment on heating of the cryostat plate together with the sample holder we have observed nearly independence of the noise on the electron temperature of the absorber, which has provided another proof of the presence of the photon noise in the first experiment.
The composition of dark matter is one of the puzzling topics in astrophysics. To address this issue, several experiments searching for the existence of axions have been designed, built and realized in the last twenty years. Among all the others, light shining through walls experiments promise to push the exclusion limits to lower energies. For this reason, effort is put for the development of single-photon detectors operating at frequencies $<100$ GHz. Here, we review recent advancements in superconducting single-photon detection. In particular, we present two sensors based on one-dimensional Josephson junctions with the capability to be in situ tuned by simple current bias: the nanoscale transition edge sensor (nano-TES) and the Josephson escape sensor (JES). These two sensors are the ideal candidates for the realization of microwave light shining through walls (LSW) experiments, since they show unprecedented frequency resolutions of about 100 GHz and 2 GHz for the nano-TES and JES, respectively.
We describe the optical characterisation of two silicon cold-electron bolometers each consisting of a small ($32 times 14~mathrm{mu m}$) island of degenerately doped silicon with superconducting aluminium contacts. Radiation is coupled into the silicon absorber with a twin-slot antenna designed to couple to 160-GHz radiation through a silicon lens.The first device has a highly doped silicon absorber, the second has a highly doped strained-silicon absorber.Using a novel method of cross-correlating the outputs from two parallel amplifiers, we measure noise-equivalent powers of $3.0 times 10^{-16}$ and $6.6 times 10^{-17}~mathrm{W,Hz^{-1/2}}$ for the control and strained device, respectively, when observing radiation from a 77-K source. In the case of the strained device, the noise-equivalent power is limited by the photon noise.
The time-dependent fluctuations of conductivity sigma have been studied in a two-dimensional electron system in low-mobility, small-size Si inversion layers. The noise power spectrum is ~1/f^{alpha} with alpha exhibiting a sharp jump at a certain electron density n_s=n_g. An enormous increase in the relative variance of sigma is observed as n_s is reduced below n_g, reflecting a dramatic slowing down of the electron dynamics. This is attributed to the freezing of the electron glass. The data strongly suggest that glassy dynamics persists in the metallic phase.
A micrometer scale calorimeter realized by using Schottky junctions as a thermometer is presented. Combined with a hybrid experimental method, it enables simultaneous time-resolved measurements of variations in both the energy and the heat capacity of subnanolitre samples.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
