José M. Iglesias

• PhD. in Applied Physics and Technology
• PhD Student at University of Salamanca

The result of the multidisciplinary collaboration of researchers from different areas of knowledge to validate a solar radiation model is presented. The MAPsol is a 3D local-scale adaptive solar radiation model that allows us to estimate direct, diffuse, and reflected irradiance for clear sky conditions. The model includes the adaptation of the mes...

The result of the multidisciplinary collaboration of researchers from different areas of knowledge to validate a solar radiation model is presented. The MAPsol is a 3D local-scale adaptive solar radiation model that allows to estimate direct, diffuse and reflected irradiance for clear sky conditions. The model includes the adaptation of the mesh to...

The transient high-frequency noise response of two-dimensional MoS2 under abrupt large signal switching field conditions is studied by means of an ensemble Monte Carlo simulator. Low-to-high and high-to-low transitions are analyzed at low (77 K) and room temperature, considering several underlying substrates. The incorporation of stochastic individ...

The effect of degeneracy and the impact of free-carrier screening on a low-field mobility and a high-field drift velocity in MoS 2 and WS 2 are explored using an in-house ensemble Monte Carlo simulator. Electron low field mobility increases to 8400 cm ² /Vs for MoS 2 and to 12040 cm ² /Vs for WS 2 when temperature decreases to 77 K and carrier conc...

Graphene on different substrates, such as SiO2, h-BN and Al2O3, has been subjected to oscillatory electric fields to analyse the response of the carriers in order to explore the generation of terahertz radiation by means of high-order harmonic extraction. The properties of the ensemble Monte Carlo simulator employed for such study have allowed us t...

In this paper, we explore the capabilities of MoS2 and WS2 2D monolayers to produce radiation in the terahertz range by the generation of high-order harmonics. This phenomenon, which is a result of the non-linear response of the electronic carrier population to the applied electric field, is studied by using a particle ensemble stochastic simulatio...

The microscopic transport properties of electrons and holes in MoS2, MoSe2, WS2 and WSe2 are studied by means of an ensemble Monte Carlo simulator. Moreover, instantaneous carrier velocity fluctuations are analyzed in depth from a microscopic point of view, including their power spectral density, which is directly related to thermal noise in the GH...

The importance of interband transitions on the ultrafast relaxation process in photoexcited pristine graphene is evaluated by means of an ensemble Monte Carlo simulator. Impact ionization and Auger recombination in the collinear limit are considered, together with phonon-induced generation and recombination and intraband scattering mechanisms. The...

A study of the diffusivity in Molybdenum disulfide as a function of the applied electric field and temperature has been developed in this work by means of an ensemble Monte Carlo simulator. The analysis of the different scattering types indicates that the transitions to the upper valleys have an important effect over the noise and the velocity fluc...

An ensemble Monte Carlo study of interband scattering in graphene, including impact ionization, Auger recombination and phonon-induced generation and recombination, is presented. The model rigorously considers the collinear limit condition for many-particle interband interactions in a linear dispersion bandstructure. The results show that carrier m...

Hexagonal boron nitride encapsulation significantly improves carrier transport in graphene. This paper investigates the benefit of implementing the encapsulation technique in graphene field-effect transistors (GFETs) in terms of their intrinsic radio frequency (RF) performance, adding the effect of the series resistances at the terminals. For such...

High-order harmonic generation is an interesting option to reach the THz range for generation and detection applications. In this work the time-domain and spectral behavior of carrier velocity fluctuations in free-standing graphene under the action of a high frequency alternating electric field are studied by means of an ensemble Monte Carlo simula...

The hot phonon effect is a non-equilibrium phenomenon that has an important role in high-field electronic transport in two-dimensional electron gases and in 2D materials like graphene. In this work, the influence of this effect on the electronic transport properties of silicene is investigated by means on an ensemble Monte Carlo simulator that acco...

Hexagonal boron nitride (h-BN) encapsulation has demonstrated to significantly improve carrier transport in graphene. In this work, we have investigated the benefit of implementing this encapsulation technique in graphene field-effect transistors (GFET) in terms of their radio frequency (RF) performance. For such a purpose, a drift-diffusion self-c...

Silicene is a two-dimensional buckled material with broken horizontal mirror symmetry and Dirac-like dispersion. Under such conditions, flexural acoustic (ZA) phonons play a dominant role. Consequently, it is necessary to consider some suppression mechanism for electron–phonon interactions with long wavelengths in order to reach mobilities useful f...

Silicene, the silicon analogue of graphene, is an emerging two-dimensional material with very attractive electronic properties for a wide range of applications [1]. In particular, it could be interesting to develop new nanoelectronic applications using this material due to its direct compatibility with silicon technology and the possibility of indu...

Graphene has hugely increased its quality in nanodevices thanks to hexagonal boron nitride (hBN) acting as a supporting layer. Here, we investigate to which extent hBN and channel length scaling can be exploited in graphene field-effect transistors (GFETs) to get competitive radio-frequency (RF) performances. For such a purpose, we have applied mul...

The interaction between out-of-equilibrium phonons and Joule heating in the static electron transport properties of monolayer graphene supported on SiO2 is investigated. An ensemble Monte Carlo electronic transport engine with a self-consistent out-of-equilibrium phonon population is coupled to a thermal resistive model describing the heat dissipat...

A computationally efficient modelling approach for the study of the small-signal and high-frequency noise properties of graphene is presented. The method combines stationary Monte Carlo particle simulations and analytical balance equations. Relevant parameters, like energy and velocity relaxation rates, are determined as a function of the applied e...

The quality of graphene in nanodevices has increased hugely thanks to the use of hexagonal boron nitride as a supporting layer. This paper studies to which extent hBN together with channel length scaling can be exploited in graphene field effect transistors (GFETs) to get a competitive radio frequency (RF) performance. Carrier mobility and saturati...

The influence of different substrates on the photocarrier relaxation dynamics in monolayer graphene during the early stages of thermalization and cooling is explored and analyzed by means of ensemble Monte Carlo simulations. In addition, phonon dynamics of both intrinsic and surface polar modes associated to the interface between graphene and the u...

In this paper we analyze the effects of the hot phonon and self-heating on the static electronic transport characteristics of monolayer graphene. For this purpose, the Ensemble Monte Carlo method self-consistently coupled to a thermal resistive model for the heat dissipation is employed. This way, the most relevant mechanisms that limit the drift v...

The small signal response and noise temperature in graphene under non-degenerated conditions is evaluated by means of a combined Monte Carlo-balance equations approach. The method correctly predicts the qualitative behavior of the most relevant quantities, such as real part of the differential mobility or diffusion coefficient, being much more comp...

A numerical method for obtaining the frequency-dependent noise temperature in monolayer graphene is presented. From the mobility and diffusion coefficient values provided by Monte Carlo simulation, the noise temperature in graphene is studied up to the THz range, considering also the influence of different substrate types. The influence of the appl...

In this paper we present an analysis of the velocity fluctuations during transient regimes arising from an abrupt shift of the electric field in bulk monolayer graphene. For this purpose a material Ensemble Monte Carlo simulator is used to examine these fluctuations by means of the transient autocorrelation function and power spectral density. The...

We study, by means of a Monte Carlo simulator, the hot phonon effect on the relaxation dynamics in photoexcited graphene and its quantitative impact as compared to considering an equilibrium phonon distribution. Our multi-particle approach indicates that neglecting the hot phonon effect significantly underestimates the relaxation times in photoexci...

We study, by means of a Monte Carlo simulator, the hot phonon effect on the relaxation dynamics in photoexcitedgraphene and its quantitative impact as compared with considering an equilibrium phonon distribution. Our multi-particle approach indicates that neglecting the hot phonon effect significantly underestimates the relaxation times in photoexc...

The influence of charged impurities on the transport properties of graphene, including the diffusion coefficient at low and high electric fields, is investigated by means of an ensemble Monte Carlo simulator. Three different possible substrates are considered, h-BN, SiC and SiO2. The results show the importance of impurity scattering in degrading t...

In this work we use the Monte Carlo method to simulate the photoexcited carrier relaxation dynamics in suspended monolayer graphene to unveil the role of the different scattering mechanisms involved. The results show a strong activity of carrier-carrier and carrier-optical phonon interactions in the very early stages of the relaxation process drivi...

The main objective of this paper is to study the effects of variability in the position of the gates in Double-Gate Shottky-barrier MOSFETs by means of the Monte Carlo method. Taking a device with double gate and perfectly aligned contacts as a starting point, simulations were systematically performed to assess the impact of different types of gate...

In this work, the influence of the underlying substrate on the mobility and electronic transport in graphene is evaluated by means of an ensemble Monte Carlo simulator. The substrates considered are h-BN, SiC, SiO2 and HfO2. The substrate type strongly affects the low-field mobility, particularly at room temperature; however, at low temperature the...