Micrometer Sized Hexagonal Chromium Selenide Flakes for Cryogenic Temperature Sensors

Abstract

Nanoscale thermometers with high sensitivity are needed in domains which study quantum and classical effects at cryogenic temperatures. Here, we present a micrometer sized and nanometer thick chromium selenide cryogenic temperature sensor capable of measuring a large domain of cryogenic temperatures down to tenths of K. Hexagonal Cr-Se flakes were obtained by a simple physical vapor transport method and investigated using scanning electron microscopy, energy dispersive X-ray spectrometry and X-ray photoelectron spectroscopy measurements. The flakes were transferred onto Au contacts using a dry transfer method and resistivity measurements were performed in a temperature range from 7 K to 300 K. The collected data have been fitted by exponential functions. The excellent fit quality allowed for the further extrapolation of resistivity values down to tenths of K. It has been shown that the logarithmic sensitivity of the sensor computed over a large domain of cryogenic temperature is higher than the sensitivity of thermometers commonly used in industry and research. This study opens the way to produce Cr-Se sensors for classical and quantum cryogenic measurements.

Synthesis of WS2 Ultrathin Films by Magnetron Sputtering Followed by Sulfurization in a Confined Space

“…The discrepancy in thickness between the estimated value at deposition and that determined through XRR can be attributed to superficial oxidation of the W film and to its disordered structure. In the case of the pr WS2 layer, the estimated thickness was found to be 1.3 nm, with a mean mass density of 7.3 g/cm 3 . This result is close to the target thickness and to the density of a bulk WS 2 monocrystal, which is 7.5 g/cm 3 .…”

“…In the case of the pr WS2 layer, the estimated thickness was found to be 1.3 nm, with a mean mass density of 7.3 g/cm 3 . This result is close to the target thickness and to the density of a bulk WS 2 monocrystal, which is 7.5 g/cm 3 .…”

“…These fits were generated using the Leptos fitting program, which modeled the films with specific parameters including thickness, electronic density, and surface roughness. For the pr W layer, the fitted diagrams estimated a film thickness of 2.9 nm, with a mean mass density of 12.9 g/cm 3 . This value is notably lower than the density of a bulk W monocrystal, which stands at 19.25 g/cm 3 .…”

“…For the pr W layer, the fitted diagrams estimated a film thickness of 2.9 nm, with a mean mass density of 12.9 g/cm 3 . This value is notably lower than the density of a bulk W monocrystal, which stands at 19.25 g/cm 3 . The discrepancy in thickness between the estimated value at deposition and that determined through XRR can be attributed to superficial oxidation of the W film and to its disordered structure.…”

“…The exploration of atomically layered crystalline materials has surged in recent years, driven by their unique physical properties and potential applications in various technological domains [1][2][3][4]. These materials consist of identically ordered monolayers of atoms arranged in a planar parallel fashion.…”