Heating process in the pre-Breakdown regime of the Quantum Hall Efect : a size dependent effect

Our study presents experimental measurements of the contact and longitudinal voltage drops in Hall bars, as a function of the current amplitude. We are interested in the heating phenomenon which takes place before the breakdown of the quantum Hall effect, i.e. the pre-breakdown regime. Two types of samples has been investigated, at low temperature (4.2 and 1.5K) and high magnetic field (up to 13 T). The Hall bars have several different widths, and our observations clearly demonstrate that the size of the sample influences the heating phenomenon. By measuring the critical currents of both contact and longitudinal voltages, as a function of the filling factor (around $i=2$), we highlight the presence of a high electric field domain near the source contact, which is observable only in samples whose width is smaller than 400 microns.Comment: 4 pages, 5 igures, 7th International Symposium of Research in High Magnetic Fields, to be published in physica

Terahertz generation and detection by plasma waves in nanometer gate high electron mobility transistors

ISBN: 92-990035-0-5International audienc

Terahertz generation and detection by plasma waves in nanometer gate high electron mobility transistors

ISBN: 92-990035-0-5International audienc

THz emission related to hot plasmons and plasma wave instability in field effect transistors

International audienc

Magneto-Transport and Optical Characterization of Amorphous Silicon Tandem Cell

Commercial amorphous silicon tandem cells have been thoroughly characterized combining optical and transport measurements. Using several optical techniques (spectroscopic ellipsometry, reflectivity, optical transmission and micro-Raman spectroscopy), magneto-transport (Hall density and mobility) and electrical I-V and C-V measurements we have obtained information about the main physical parameters of the device (electronic density, mobility, real and complex dielectric function and absorption coefficient)

Solar Cell Manufacturing: As-cut mc-Si Wafers Discrimination Using Magnetotransport, Optical and Lifetime Measurements

Multicrystalline silicon (mc-Si) wafers from different suppliers have been characterized combining optical and transport measurements. Using several optical techniques, namely spectroscopic ellipsometry and optical absorption, together with magneto-transport measurements such as Hall density and mobility, resistance and capacitance, and their temperature dependence, one can obtain very precise information about main physical parameters such as electronic density, mobility, real and complex refractive index, absorption coefficient and strains on the grain boundaries. This preliminary study, based on two different physical approaches, aims to qualify wafer suppliers on the basis of several non-conventional properties of mc-Si wafers that can be of crucial interest to complete the scarce information usually included in the classical wafer manufacturer\u2019s datasheet. Thus, this type of characterization can be considered as crucial for solar cells producers, as a first quality control step