Temperature resistance coefficient of doped with rare earth elements nanostructured silicon films

The regularities of changes in the concentration of an electrically active dopant in a nanostructured silicon film by changing the electrical resistivity depending on the doping conditions were investigated. The dependences of the changes in the obtained structures doped with rare-earth elements, such as La, Eu, Sm, Dy, Gd (lanthanides), on nanostructured silicon films are determined. The regularities of the obtained films changes and the temperature coefficient of resistance (TCR) change depending on the formation conditions are established. The regularities of the TCR are shown depending on the selected conditions for doping or non-doping of nanostructured silicon films with various impurities. It is shown that the main conditions under which the effect and change in the temperature coefficient of resistors resistance on thin films using rare-earth elements, such as oxygen, boron and phosphorus in the bulk of the film, is considered to be the temperature effect after deposition.

Влияние частоты переменного электрического поля на температурные спектры импеданса керамического мультиферроика LuFe-=SUB=-2-=/SUB=-O-=SUB=-4-=/SUB=-

Temperature impedance spectra are measured on LuFe_2O_4 ceramic multiferroics over a temperature range of 100–400 K, upon applying a sinusoidal voltage with a frequency varying between 20 Hz and 120MHz. At signal frequencies of 30–70 MHz, spectra exhibit features such as an abnormal positive temperature resistance coefficient within the temperature range of 200–260 K, which are interpreted in the context of the generalized barrier model.

Modeling, Design, and Fabrication of Self-Doping Si1−xGex/Si Multiquantum Well Material for Infrared Sensing

The paper presents the study of band distributions and thermoelectric properties of self-doping Si1−xGex/Si multiquantum well material for infrared detection. The simulations of different structures (including boron doping, germanium concentrations, and SiGe layer thickness) have been conducted. The critical thickness of SiGe layer grown on silicon substrate has also been illustrated in the paper. The self-doping Si1−xGex/Si multiquantum well material was epitaxially grown on SOI substrate with reduced pressure chemical vapor deposition. Each layer of the material is clear in the SEM. TheI-Vcharacterizations and temperature resistance coefficient (TCR) tests were also performed to show the thermoelectric properties. The TCR was about −3.7%/K at room temperature in the experiments, which is competitive with the other thermistor materials. The material is a low noise material, whose root mean square noise is 1.89 mV in the experiments.

NOISE MEASUREMENTS ON NbN THIN FILMS WITH A NEGATIVE TEMPERATURE RESISTANCE COEFFICIENT DEPOSITED ON SAPPHIRE AND ON SiO2

We characterize granular NbN x thin cermet films deposited on either sapphire substrate or on SiO 2 and compare the 1/f noise at 300 K and 80 K. The films were characterized with an impedance analyzer from 20 Hz to 1 MHz and analyzed as a resistor R in parallel with a capacitor C. The calculated noise voltage spectral density SvTh of the sample is in agreement with the experimentally observed noise for unbiased samples. The noise measurements on biased samples show 1/f noise. We checked that contact noise does not contribute to our measurements. The 1/f noise was compared for the films deposited on the silicon substrate and on the sapphire. Finally a model is proposed to explain the observed trends in the temperature resistance coefficient (TRC < 0 for all samples) and the relative 1/f noise at 300 K and 80 K with the composition x = N/Nb of the layers.