arXiv subjects

J. A. Garrido

Publications and source records attributed to J. A. Garrido.

3 recordsLinked to original sources

arXiv2025

Physics-Based Compact Modeling for the Drain Current Variability in Single-Layer Graphene FETs

For the growth of emerging graphene field-effect transistor (GFET) technologies, a thorough characterization of on-wafer variability is required. Here, we report for the first time a physics-based compact model, which precisely describes the drain current (ID) fluctuations of monolayer GFETs. Physical mechanisms known to generate 1/f noise in transistors, such as carrier number and Coulomb scattering mobility fluctuations, are also revealed to cause ID variance. Such effects are considered in the model by being activated locally in the channel and the integration of their contributions from source to drain results in total variance. The proposed model is experimentally validated from a statistical population of three different-sized solution-gated (SG) GFETs from strong p- to strong n-type bias conditions. A series resistance ID variance model is also derived mainly contributing at high carrier densities.

cond-mat.mes-hall↗

arXiv2021

Heat dissipation in few-layer MoS2 and MoS2/hBN heterostructure

State-of-the-art fabrication and characterization techniques have been employed to measure the thermal conductivity of suspended, single-crystalline MoS2 and MoS2/hBN heterostructures. Two-laser Raman scattering thermometry was used combined with real time measurements of the absorbed laser power, which allowed us to determine the thermal conductivities without any assumptions. Measurements on MoS2 layers with thicknesses of 5 and 14 exhibit thermal conductivity in the range between 12 and 24 Wm-1K-1. Additionally, after determining the thermal conductivity of a selected MoS2 sample, an hBN flake was transferred onto it and the effective thermal conductivity of the heterostructure was subsequently measured. Remarkably, despite that the thickness of the hBN layer was less than a third of the thickness of the MoS2 layer, the heterostructure showed an almost eight-fold increase in the thermal conductivity, being able to dissipate more than 10 times the laser power without any visible sign of damage. These results are consistent with a high thermal interface conductance between MoS2 and hBN and an efficient in-plane heat spreading driven by hBN. Indeed, we estimate G 70 MWm-2K-1 which is significantly higher than previously reported values. Our work therefore demonstrates that the insertion of hBN layers in potential MoS2 based devices holds the promise for efficient thermal management.

cond-mat.mes-hall↗

arXiv2010

Chemical control of the charge state of nitrogen-vacancy centers in diamond

We investigate the effect of surface termination on the charge state of nitrogen vacancy centers, which have been ion-implanted few nanometers below the surface of diamond. We find that, when changing the surface termination from oxygen to hydrogen, previously stable NV- centers convert into NV0 and, subsequently, into an unknown non-fluorescent state. This effect is found to depend strongly on the implantation dose. Simulations of the electronic band structure confirm the dissappearance of NV- in the vicinity of the hydrogen-terminated surface. The band bending, which induces a p-type surface conductive layer leads to a depletion of electrons in the nitrogen vacancies close to the surface. Therefore, hydrogen surface termination provides a chemical way for the control of the charge state of nitrogen-vacancy centers in diamond. Furthermore, it opens the way to an electrostatic control of the charge state with the use of an external gate electrode.

cond-mat.mtrl-sci↗