Person:
González Díaz, Germán

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First Name
Germán
Last Name
González Díaz
URI
https://hdl.handle.net/20.500.14352/75016
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
Department
Estructura de la Materia, Física Térmica y Electrónica
Area
Electrónica
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2020 - 20236
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Now showing 1 - 6 of 6
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    Electronic transport properties of Ti-supersaturated Si processed by rapid thermal annealing or pulsed-laser melting
    (Semiconductor Science and Technology, 2022) Olea Ariza, Javier; González Díaz, Germán; Pastor Pastor, David; García Hemme, Eric; Caudevilla Gutiérrez, Daniel; Algaidy, S; Pérez-Zenteno, F.; Duarte-Cano, S.; García Hernansanz, Rodrigo; Prado Millán, Álvaro Del; San Andrés Serrano, Enrique; Martil De La Plaza, Ignacio
    In the scope of supersaturated semiconductors for infrared detectors, we implanted Si samples with Ti at high doses and processed them by rapid thermal annealing (RTA) to recover the crystal quality. Also, for comparative purposes, some samples were processed by pulsed-laser melting. We measured the electronic transport properties at variable temperatures and analyzed the results. The results indicate that, for RTA samples, surface layers with a high Ti concentration have negligible conductivity due to defects. In contrast, the implantation tail region has measurable conductivity due to very high electron mobility. This region shows the activation of a very shallow donor and a deep donor level. While deep levels have been previously reported for Ti in Si, such a shallow level has never been measured, and we suggest that it originates from Ti-Si complexes. Finally, a decoupling effect between the implanted layer and the substrate seems to be present, and a bilayer model is applied to fit the measured properties. The fitted parameters follow the Meyer–Neldel rule. The role of the implantation tails in Si supersaturated with Ti is revealed in this work.
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    Ti supersaturated Si by microwave annealing processes
    (Semiconductor Science and Technology, 2023) Olea Ariza, Javier; González Díaz, Germán; Pastor Pastor, David; García Hemme, Eric; Caudevilla Gutiérrez, Daniel; Algaidy, S.; Perez Zenteno, F.; Duarte Cano, S.; García Hernansanz, Rodrigo; Prado Millán, Álvaro Del; San Andrés Serrano, Enrique; Martil De La Plaza, Ignacio; Lee, Yao-Jen; Hong, Tzu-Chieh; Chao, Tien-Sheng
    Microwave annealing (MWA) processes were used for the first time to obtain Ti supersaturated Si. High Ti doses were ion implanted on Si substrates and subsequently MWA processed to recrystallize the amorphous layer. The resulting layers were monocrystalline with a high density of defects. Ti depth profiles indicate that diffusion is avoided once recrystallization is produced. Finally, the electronic transport properties measurements point to a decoupling effect between the Si:Ti layer and the substrate. The implanted layer present also a shallow donor and very high Hall mobility.
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    Project number: 244
    Aula Virtual de Electrónica
    (2021) Prado Millán, Álvaro Del; González Díaz, Germán; Martil De La Plaza, Ignacio; San Andrés Serrano, Enrique; Sánchez Balmaseda, Margarita María; Franco Peláez, Francisco Javier; Olea Ariza, Javier; García Hemme, Eric; Pastor Pastor, David; García Hernansanz, Rodrigo; Caudevilla Gutiérrez, Daniel
    El proyecto ha consistido en la creación de un espacio virtual en Moodle para publicar contenidos complementarios para las asignaturas relacionadas con el área de la Electrónica.
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    On the Optoelectronic Mechanisms Ruling Ti-hyperdoped Si Photodiodes
    (Advanced electronic materials, 2022) García Hemme, Eric; Caudevilla Gutiérrez, Daniel; Algaidy, Sari; Pérez Zenteno, Francisco José; García Hernansanz, Rodrigo; Olea Ariza, Javier; Pastor Pastor, David; Prado Millán, Álvaro Del; San Andrés Serrano, Enrique; Martil De La Plaza, Ignacio; González Díaz, Germán
    This work deepens the understanding of the optoelectronic mechanisms ruling hyperdoped-based photodevices and shows the potential of Ti hyperdoped-Si as a fully complementary metal-oxide semiconductor compatible material for room-temperature infrared photodetection technologies. By the combination of ion implantation and laser-based methods, approximate to 20 nm thin hyperdoped single-crystal Si layers with a Ti concentration as high as 10(20) cm(-3) are obtained. The Ti hyperdoped Si/p-Si photodiode shows a room temperature rectification factor at +/- 1 V of 509. Analysis of the temperature-dependent current-voltage characteristics shows that the transport is dominated by two mechanisms: a tunnel mechanism at low bias and a recombination process in the space charge region at high bias. A room-temperature sub-bandgap external quantum efficiency (EQE) extending to 2.5 mu m wavelength is obtained. Temperature-dependent spectral photoresponse behavior reveals an increase of the EQE as the temperature decreases, showing a low-energy photoresponse edge at 0.45 eV and a high-energy photoresponse edge at 0.67 eV. Temperature behavior of the open-circuit voltage correlates with the high-energy photoresponse edge. A model is proposed to relate the optoelectronic mechanisms to sub-bandgap optical transitions involving an impurity band. This model is supported by numerical semiconductor device simulations using the SCAPS software.
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    Project number: 283
    Integración de la formación teórica y experimental en el área de la Electrónica mediante el desarrollo de una plataforma de demostración del comportamiento real de los circuitos desarrollados en la docencia teórica
    (2020) San Andrés Serrano, Enrique; González Díaz, Germán; Prado Millán, Álvaro Del; Olea Ariza, Javier; Caudevilla Gutiérrez, Daniel; Herrera Fernández, Fernando; Paz López, Antonio
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    On the properties of GaP supersaturated with Ti
    (Journal of alloys and compounds, 2020) Olea Ariza, Javier; Algaidy, S.; Prado Millán, Álvaro Del; García Hemme, Eric; García Hernansanz, Rodrigo; Montero, Daniel; Caudevilla Gutiérrez, Daniel; González Díaz, Germán; Soria, E.; Gonzalo, J.
    We have fabricated GaP supersaturated with Ti by means of ion implantation and pulsed-laser melting to obtain an intermediate band material with applications in photovoltaics. This material has a strong sheet photoconductance at energies below the bandgap of GaP and it seems to be passivated by a Ga defective GaPO oxide layer during the laser process. Passivation is consistently analyzed by sheet photoconductance and photoluminescence measurements. We report on the structural quality of the resulting layers and analyze the energy of the new optical transitions measured on GaP:Ti. A collapse found in the sheet photoconductance spectra of GaP:Ti samples fabricated on undoped substrates is explained by the negative photoconductivity phenomenon. (C) 2019 Elsevier B.V. All rights reserved.