Characterization of GaAs-Based Three-Branch Nanowire Junction Devices by Light-Induced Local Conductance Modulation Method

Nonlinear voltage transfer characteristics in GaAs-based three-branch nanowire junction (TBJ) devices were investigated by a light-induced local conductance modulation method. In this measurement system, the conductance in the device was locally increased by focused laser light irradiation. The nonlinear transfer curve was greatly changed when the laser light was irradiated on the positively biased branch. The conductance domain was found to exist at the end of the positively biased branch of the TBJ by scanning the light position. When a SiNx thin layer was deposited on the nanowire surface, the surface potential was increased and the nonlinearity in the transfer curve was reinforced simultaneously. The obtained results suggest that the asymmetric channel depletion model is appropriate for the observed nonlinearity mechanism in the GaAs TBJ at room temperature

RF doubling and rectification in Three-Terminal Junctions: experimental characterization and Monte Carlo analysis

International audienc

Calculation of Response matrix of a BSS with 6LiI scintillator

The response matrix of a Bonner sphere spectrometer was calculated using MCNP 4C and MCNPX 2.4.0 codes. As thermal neutron detector a 0.4 cm ×∅ 0.4 cm 6LiI which is located at the center of a set of polyethylene spheres. The response was calculated for 0, 2, 3, 5, 8, 10, and 12 inches-diameter polyethylene spheres for neutrons whose energy goes from 2.50E(-8) to 100 MeV. The response matrix was calculated for 23 neutron energies, the response functions were energy-interpolated to 51 neutron energies and were compared with a matrix response reported in the literature, in this comparison both response matrices are in agreement. The main differences were found in the bare detector and are attributed to the irradiation conditions and cross sections, for the other detectors the differences are due to the cross sections libraries.Se calcul´o la matriz de respuesta de un espectr´ometro de Esferas de Bonner utilizando los c´odigos Monte Carlo MCNP 4C y MCNPX 2.4.0. El detector de neutrones t´ermicos del espectr´ometro es un centellador cil´ındrico, 0.4 cm ×∅ 0.4 cm, de 6LiI, que se ubica en el centro de esferas de polietileno. La respuesta se obtuvo para esferas cuyo di´ametro es 0, 2, 3, 5, 8, 10 y 12 pulgadas y para fuentes monoenerg´eticas de neutrones de 2.50E(-8) to 100 MeV. La matriz se calcul´o para 23 fuentes monoenerg´eticas, las funciones de respuesta se interpolaron a 51 energ´ıas que se compararon con las correspondientes reportadas en la literatura. Se encontr´o que ambas matrices son coincidentes, excepto para neutrones de baja y alta energ´ıa; esta diferencia es atribuida a las condiciones de irradiaci´on utilizadas en ambos estudios y a las secciones eficaces

Non-linear thermal resistance model for the simulation of high power GaN-based devices

We report on the modeling of self-heating in GaN-based devices. While a constant thermal resistance is able to account for the self-heating effects at low power, the decrease of the thermal conductance of semiconductors when the lattice temperature increases, makes necessary the use of temperature dependent thermal resistance models. Moreover, in order to correctly account for the steep increase of the thermal resistance of GaN devices at high temperature, where commonly used models fail, we propose a non-linear model which, included in an electro-thermal Monte Carlo simulator, is able to reproduce the strongly non-linear behavior of the thermal resistance observed in experiments at high DC power levels. The accuracy of the proposed non-linear thermal resistance model has been confirmed by means of the comparison with pulsed and DC measurements made in devices specifically fabricated on doped GaN, able to reach DC power levels above 150 W mm-1 at biases below 30 V.National Research Foundation (NRF)This work was partially supported by the NRF2017-NRFANR003 GaNGUN project, the Spanish MINECO and FEDER through project TEC2017-83910-R and the Junta de Castilla y León and FEDER through project SA254P18