Effect of the Front and Back Illumination on Sub-Terahertz Detection Using n-Channel Strained-Silicon MODFETs

[EN] Plasma waves in semiconductor gated 2-D systems can be used to efficiently detect Terahertz (THz) electromagnetic radiation. This work reports on the response of a strained-Si Modulation-doped Field-Effect Transistor (MODFET) under front and back sub-THz illumination. The response of the MODFET has been characterized using a two-tones solid-state continuous wave source at 0.15 and 0.30 THz. The DC drain-to-source voltage of 500-nm gate length transistors transducing the sub-THz radiation (photovoltaic mode) exhibited a non-resonant response in agreement with literature results. Two configurations of the illumination were investigated: (i) front side illumination in which the transistor was shined on its top side, and (ii) back illumination side where the device received the sub-THz radiation on its bottom side, i.e., on the Si substrate. Under excitation at 0.15 THz clear evidence of the coupling of terahertz radiation by the bonding wires was found, this coupling leads to a stronger response under front illumination than under back illumination. When the radiation is shifted to 0.3 THz, as a result of a lesser efficient coupling of the EM radiation through the bonding wires, the response under front illumination was considerably weakened while it was strengthened under back illumination. Electromagnetic simulations explained this behavior as the magnitude of the induced electric field in the channel of the MODFET was considerably stronger under back illumination.This research was funded by the Ministerio de Ciencia, Investigacion y Universidades of Spain andFEDER (ERDF: European Regional Development Fund) under the Research Grants numbers RTI2018-097180-B-100 and TEC2016-78028-C3-3-P and FEDER/Junta de Castilla y Leon Research Grant number SA256P18. Also by Conselleria d'Educacio, lnvestigacio, Cultura i Esport, Generalitat Valenciana (Spain) through the grant AIC0/2019/018. The APC received no external funding.Delgado-Notario, JA.; Calvo-Gallego, J.; Velázquez-Pérez, JE.; Ferrando Bataller, M.; Fobelets, K.; Meziani, YM. (2020). Effect of the Front and Back Illumination on Sub-Terahertz Detection Using n-Channel Strained-Silicon MODFETs. Applied Sciences. 10(17):1-9. https://doi.org/10.3390/app10175959S191017Lewis, R. A. (2019). A review of terahertz detectors. Journal of Physics D: Applied Physics, 52(43), 433001. doi:10.1088/1361-6463/ab31d5Dragoman, D., & Dragoman, M. (2004). Terahertz fields and applications. Progress in Quantum Electronics, 28(1), 1-66. doi:10.1016/s0079-6727(03)00058-2Mittleman, D. M. (2017). Perspective: Terahertz science and technology. Journal of Applied Physics, 122(23), 230901. doi:10.1063/1.5007683Pawar, A. Y., Sonawane, D. D., Erande, K. B., & Derle, D. V. (2013). Terahertz technology and its applications. Drug Invention Today, 5(2), 157-163. doi:10.1016/j.dit.2013.03.009Federici, J., & Moeller, L. (2010). Review of terahertz and subterahertz wireless communications. Journal of Applied Physics, 107(11), 111101. doi:10.1063/1.3386413Federici, J. F., Schulkin, B., Huang, F., Gary, D., Barat, R., Oliveira, F., & Zimdars, D. (2005). THz imaging and sensing for security applications—explosives, weapons and drugs. Semiconductor Science and Technology, 20(7), S266-S280. doi:10.1088/0268-1242/20/7/018Dyakonov, M., & Shur, M. (1993). Shallow water analogy for a ballistic field effect transistor: New mechanism of plasma wave generation by dc current. Physical Review Letters, 71(15), 2465-2468. doi:10.1103/physrevlett.71.2465Dyakonov, M., & Shur, M. (1996). Detection, mixing, and frequency multiplication of terahertz radiation by two-dimensional electronic fluid. IEEE Transactions on Electron Devices, 43(3), 380-387. doi:10.1109/16.485650Tauk, R., Teppe, F., Boubanga, S., Coquillat, D., Knap, W., Meziani, Y. M., … Shur, M. S. (2006). Plasma wave detection of terahertz radiation by silicon field effects transistors: Responsivity and noise equivalent power. Applied Physics Letters, 89(25), 253511. doi:10.1063/1.2410215Rumyantsev, S. L., Fobelets, K., Veksler, D., Hackbarth, T., & Shur, M. S. (2008). Strained-Si modulation doped field effect transistors as detectors of terahertz and sub-terahertz radiation. Semiconductor Science and Technology, 23(10), 105001. doi:10.1088/0268-1242/23/10/105001Javadi, E., Delgado-Notario, J. A., Masoumi, N., Shahabadi, M., Velázquez-Pérez, J. E., & Meziani, Y. M. (2018). Continuous Wave Terahertz Sensing Using GaN HEMTs. physica status solidi (a), 215(11), 1700607. doi:10.1002/pssa.201700607Delgado-Notario, J. A., Clericò, V., Diez, E., Velázquez-Pérez, J. E., Taniguchi, T., Watanabe, K., … Meziani, Y. M. (2020). Asymmetric dual-grating gates graphene FET for detection of terahertz radiations. APL Photonics, 5(6), 066102. doi:10.1063/5.0007249Lewis, R. A. (2014). A review of terahertz sources. Journal of Physics D: Applied Physics, 47(37), 374001. doi:10.1088/0022-3727/47/37/374001Delgado-Notario, J., Velazquez-Perez, J., Meziani, Y., & Fobelets, K. (2018). Sub-THz Imaging Using Non-Resonant HEMT Detectors. Sensors, 18(2), 543. doi:10.3390/s18020543Gaspari, V., Fobelets, K., Velazquez-Perez, J. E., Ferguson, R., Michelakis, K., Despotopoulos, S., & Papavassilliou, C. (2004). Effect of temperature on the transfer characteristic of a 0.5 μm-gate Si:SiGe depletion-mode n-MODFET. Applied Surface Science, 224(1-4), 390-393. doi:10.1016/j.apsusc.2003.08.066Fobelets, K., Jeamsaksiri, W., Papavasilliou, C., Vilches, T., Gaspari, V., Velazquez-Perez, J. E., … König, U. (2004). Comparison of sub-micron Si:SiGe heterojunction nFETs to Si nMOSFET in present-day technologies. Solid-State Electronics, 48(8), 1401-1406. doi:10.1016/j.sse.2004.01.017Delgado Notario, J. A., Javadi, E., Calvo-Gallego, J., Diez, E., Velázquez, J. E., Meziani, Y. M., & Fobelets, K. (2016). Sub-Micron Gate Length Field Effect Transistors as Broad Band Detectors of Terahertz Radiation. International Journal of High Speed Electronics and Systems, 25(03n04), 1640020. doi:10.1142/s0129156416400206Sakowicz, M., Łusakowski, J., Karpierz, K., Grynberg, M., Gwarek, W., Boubanga, S., … Studart, N. (2010). A High Mobility Field-Effect Transistor as an Antenna for sub-THz Radiation. doi:10.1063/1.3295528Knap, W., Teppe, F., Meziani, Y., Dyakonova, N., Lusakowski, J., Boeuf, F., … Shur, M. S. (2004). Plasma wave detection of sub-terahertz and terahertz radiation by silicon field-effect transistors. Applied Physics Letters, 85(4), 675-677. doi:10.1063/1.177503

Phonon-mediated room-temperature quantum Hall transport in graphene

The quantum Hall (QH) effect in two-dimensional electron systems (2DESs) is conventionally observed at liquid-helium temperatures, where lattice vibrations are strongly suppressed and bulk carrier scattering is dominated by disorder. However, due to large Landau level (LL) separation (~2000 K at B = 30 T), graphene can support the QH effect up to room temperature (RT), concomitant with a non-negligible population of acoustic phonons with a wave-vector commensurate to the inverse electronic magnetic length. Here, we demonstrate that graphene encapsulated in hexagonal boron nitride (hBN) realizes a novel transport regime, where dissipation in the QH phase is governed predominantly by electron-phonon scattering. Investigating thermally-activated transport at filling factor 2 up to RT in an ensemble of back-gated devices, we show that the high B-field behaviour correlates with their zero B-field transport mobility. By this means, we extend the well-accepted notion of phonon-limited resistivity in ultra-clean graphene to a hitherto unexplored high-field realm.Comment: 17 pages, 4 figures. Supplementary information available at https://doi.org/10.1038/s41467-023-35986-

Sub-THz Imaging Using Non-Resonant HEMT Detectors

Plasma waves in gated 2-D systems can be used to efficiently detect THz electromagnetic radiation. Solid-state plasma wave-based sensors can be used as detectors in THz imaging systems. An experimental study of the sub-THz response of II-gate strained-Si Schottky-gated MODFETs (Modulation-doped Field-Effect Transistor) was performed. The response of the strained-Si MODFET has been characterized at two frequencies: 150 and 300 GHz: The DC drain-to-source voltage transducing the THz radiation (photovoltaic mode) of 250-nm gate length transistors exhibited a non-resonant response that agrees with theoretical models and physics-based simulations of the electrical response of the transistor. When imposing a weak source-to-drain current of 5 μA, a substantial increase of the photoresponse was found. This increase is translated into an enhancement of the responsivity by one order of magnitude as compared to the photovoltaic mode, while the NEP (Noise Equivalent Power) is reduced in the subthreshold region. Strained-Si MODFETs demonstrated an excellent performance as detectors in THz imaging

Towards Understanding the Raman Spectrum of Graphene Oxide: The Effect of the Chemical Composition

Raman spectroscopy is a technique widely used to detect defects in semiconductors because it provides information of structural or chemical defects produced in its structure. In the case of graphene monolayer, the Raman spectrum presents two bands centered at 1582 cm−1 (G band) and 2700 cm−1 (2D band). However, when the periodic lattice of graphene is broken by different types of defects, new bands appear. This is the situation for the Raman spectrum of graphene oxide. It is well established that the existence of these bands, the position and the intensity or width of peaks can provide information about the origin of defects. However, in the case of the graphene oxide spectrum, we can find in the literature several discrepant results, probably due to differences in chemical composition and the type of defects of the graphene oxide used in these studies. Besides, theoretical calculations proved that the shape of bands, intensity and width, and the position of graphene oxide Raman spectrum depend on the atomic configuration. In the current work, we will summarize our current understanding of the effect of the chemical composition on the Raman spectrum of graphene oxide. Finally, we apply all this information to analyze the evolution of the structure of graphene oxide during the thermal annealing of the heterostructures formed by graphene oxide sandwiches in a hexagonal boron nitride

Numerical Study of the Coupling of Sub-Terahertz Radiation to n-Channel Strained-Silicon MODFETs

[EN] This paper reports on a study of the response of a T-gate strained-Si MODFETs (modulation-doped field-effect transistor) under continuous-wave sub-THz excitation. The sub-THz response was measured using a two-tones solid-state source at 0.15 and 0.30 THz. The device response in the photovoltaic mode was non-resonant, in agreement with the Dyakonov and Shur model for plasma waves detectors. The maximum of the photoresponse was clearly higher under THz illumination at 0.15 THz than at 0.3 THz. A numerical study was conducted using three-dimensional (3D) electromagnetic simulations to delve into the coupling of THz radiation to the channel of the transistor. 3D simulations solving the Maxwell equations using a time-domain solver were performed. Simulations considering the full transistor structure, but without taking into account the bonding wires used to contact the transistor pads in experiments, showed an irrelevant role of the gate length in the coupling of the radiation to the device channel. Simulations, in contradiction with measurements, pointed to a better response at 0.3 THz than under 0.15 THz excitation in terms of the normalized electric field inside the channel. When including four 0.25 mm long bonding wires connected to the contact pads on the transistor, the normalized internal electric field induced along the transistor channel by the 0.15 THz beam was increased in 25 dB, revealing, therefore, the important role played by the bonding wires at this frequency. As a result, the more intense response of the transistor at 0.15 THz than at 0.3 THz experimentally found, must be attributed to the bonding wires.This research was funded by the Ministerio de Ciencia, Investigacion y Universidades of Spain (Spanish Ministry of Science, Innovation, and Universities) and FEDER (ERDF: European Regional Development Fund) under the Research Grants numbers RTI2018-097180-B-100, PID2019-107885GB-C3-2 and TEC2016-78028-C3-3-P and FEDER/Junta de Castilla y Leon Research Grant numbers SA256P18 and SA121P20. Also by Conselleria d'Educacio, lnvestigacio, Cultura i Esport, Generalitat Valenciana (Spain) through the grant AIC0/2019/018. The APC was funded by Universidad de Salamanca.Calvo-Gallego, J.; Delgado-Notario, JA.; Velázquez-Pérez, JE.; Ferrando Bataller, M.; Fobelets, K.; El Moussaouy, A.; Meziani, YM. (2021). Numerical Study of the Coupling of Sub-Terahertz Radiation to n-Channel Strained-Silicon MODFETs. Sensors. 21(3):1-11. https://doi.org/10.3390/s21030688S11121

Improvement of a Terahertz Detector Performance Using the Terajet Effect in a Mesoscale Dielectric Cube: Proof of Concept

[EN] Herein, a simple terahertz (THz) receiver that uses subwavelength focusing of the THz beam on the detector area is proposed. As a proof of concept, a THz detection system with an original optical coupling scheme is implemented, where the signal to be detected is coupled to a THz detector through a mesoscale dielectric particle lens. Coherent detection is successfully demonstrated with an enhancement of the detector sensitivity of about 4.3 dB, compared with that of a direct detection system with the slight decreasing (approximate to 1.67 times) of noise equivalent power value. The results show that the proposed method can reduce the size and increase the sensitivity of various THz systems, including imaging, sensing, and ranging, which would enable significant progress in different fields such as physics, medicine, biology, astronomy, security, etc.This work was partially conducted within the framework of the Tomsk Polytechnic University Competitiveness Enhancement Program. This research was supported by the Agencia Estatal de Investigacion (grants TEC2015-65477-R, TEC2016-78028-C3-3-P, and RTI2018-097180-B-100), the Consejeria de Educacion, Junta de Castilla y Leon (SA256P18), including funding by ERDF/FEDER, the Conselleria d'Educacio, lnvestigacio, Cultura i Esport, and Generalitat Valenciana through the grant AIC0/2019/018. J.A.D.N. acknowledges the Japan Society for the Promotion of Science (JSPS) for supporting the author as International Research Fellow.Minin, IV.; Minin, OV.; Delgado-Notario, JA.; Calvo-Gallego, J.; Velázquez-Pérez, JE.; Ferrando Bataller, M.; Meziani, YM. (2020). Improvement of a Terahertz Detector Performance Using the Terajet Effect in a Mesoscale Dielectric Cube: Proof of Concept. physica status solidi (RRL) - Rapid Research Letters. 14(5):1-5. https://doi.org/10.1002/pssr.201900700S1514

Generation and control of non-local chiral currents in graphene superlattices by orbital Hall effect

Graphene-based superlattices offer a new materials playground to exploit and control a higher number of electronic degrees of freedom, such as charge, spin, or valley for disruptive technologies. Recently, orbital effects, emerging in multivalley band structure lacking inversion symmetry, have been discussed as possible mechanisms for developing orbitronics. Here, we report non-local transport measurements in small gap hBN/graphene/hBN moir\'e superlattices which reveal very strong magnetic field-induced chiral response which is stable up to room temperature. The measured sign dependence of the non-local signal with respect to the magnetic field orientation clearly indicates the manifestation of emerging orbital magnetic moments. The interpretation of experimental data is well supported by numerical simulations, and the reported phenomenon stands as a formidable way of in-situ manipulation of the transverse flow of orbital information, that could enable the design of orbitronic devices.Comment: 5 pages, 5 figures and supplementary informatio

Anales de Edafología y Agrobiología Tomo 48 Número 5-12

A comparative study of the effect of soil boron on yield, yield attributes and nutrient uptake by susceptible and tolerant varieties of wheat. Por B. R. Chhipa and P. Lal.-- Suelos y vegetación de las Peñas de Aya (Navarra y Guipúzcoa. Por J. Peralta, J. Íñiguez y J. C. Bascones.-- Presencia de horizonte plácico en Ñadis (Placaquands) y Trumaos (Placudands) en el sur de Chile. Por W. Luzio, C. Barros, M. Aroncibia y S. Alcayaga.-- Retención de 0,0-Dimetil, S-(Z, Metilamino- 2, Oxoetil -Ditiofosfato (Dimetoato) por Vermiculitas homoionicas. l.-cinética del proceso. Por C. Valenzuela Calahorro, A. García Rodríguez y A. Bernalte García.-- Estudio edafogenético en suelo~ de Rañas. Distribución de hierro y aluminio. Por Mª P. García Rodr(guez, J. Forteza Bonnin, y L. F. Lorenzo Martín.-- Water retention equations and their relationship with particle size distribution and bulk density for undisturbed samples. Por A. Andriulo, N. Amiotti y C. Pecorari.-- Evolución regresiva de diversos parámetros edáficos en agroecosistemas (Cafetales, cañaverales) derivados del bosque mesófilo de montaña (México). Por N. García Calderón, F. Velasco y N. Aguilera.-- Micronutrients distribution in grown soils (Fe and Zn) prediction equations of contenta. Por A. Ruiz-Nieto, E. Barahona, S. Jaime, F. Huertas, A. Aguilar and J. Linares.-- Contenido de azufre total en muestras superficiales de suelos de la provincia de la Coruña. Por A. Merino García, C. Monterroso Martínez y E. García -Rodeja G.-- Aspectos termodinámicos de la adsorción de Clorprofan por suelos. Por G. Dios Cancela, J. A. Guillén Alfara y S. González García.-- Consideraciones acerca de las interralaciones entre suelos. Vegetación y paleoprocesos morfogenéticos en el Macizo de Ayllón y la Sierra de Alto Rey (Sector oriental del Sistema Central). Por J. J. Ibáñez Martín, F. Fernández González y A. García Alvarez.--Composición Geoquímica de unas ferricretas en el entorno de un monte isla de Ciudad Real. Por R. Jiménez Ballesta, A. M. Alvarez González, A. Gutiérrez Maroto y E. Redondo.--Relación entre algunas propiedades físico-químicas y las fracciones de fósforo en suelos naturales de Galicia (NW España). Por Mª C. Trasar Cepeda, F. Gil Sotres y F. Guitián Ojea.-- Respuesta del cultivo de tomate en enarenado y condiciones salinas a diferentes programas de fertilización fosfórica. Por M. J. Sarro, A. Saa, C. Cadahía y A. Masaguer.-- Distribución del fósforo en perfiles de suelos de Galicia (NW Spain). Por M. a C. Trasar Cepeda, F. Gil Sotres y F. Guitián Ojea.-- Influencia de la dilución en la desorción de cationes en Andosoles y suelos ándicos. Por C. D. Arbelo, J. E. García-Hernández y J. M. Hernández Moreno.-- Las marismas del Guadalquivir, reserva biogenética de plantas tolerantes a la salinidad. Por T. Marañón, L. V. García, J. M. Murillo y L. Clemente.-- Efectos del Abonado N/K sobre el contenido, interacciones y evolución del N, K, Ca y Mg en varias etapas del desarrollo de la patata. Por M. J. Lema Gesto y A. M. Cortizas.-- Estabilidad estructural de suelos afectados por sales: Revisión bibliográfica. Por E. Amezketa y R. Aragües.-- Descomposición de rastrojo de trigo, respiracion y biomasa microbiana bajo labranza convencional y siembra directa. Por O. J. Santanatoglia, R. Alvarez, P. E. Daniel, G. M. Brazzola y R. García.-- Factores formadores y características generales de los Luvisoles desarrollados sobre materiales calizos y su distribución en la provincia de Valencia. Por Mª D. Soriano Soto.-- Propiedades de intercambio iónico en tobas sálicas pumíticas del sur de la Isla de Tenerife. Por J. E. García Hernández, J. S. Notario del Pino y M. González Martín.-- Las reacciones lentas del fósforo en suelos gallegos: III. Experiencias de incubación: b) Comparación de las técnicas Bray II, Olsen y electroultrafiltración (EUF) para reflejar las variaciones con el tiempo en la extracción de fósforo. Por E. de Blas Varela, F. Gil Sotres y F. Guitián.-- Crecimiento y producción de genotipos procedentes de Haploides de Nicotiana tabacum L. seleccionados en cámara de bajo contenido en C02. Por E. Delgado y H. Medrano.-- Características foliares de genotipos de Nicotiana tabacum L. obtenidos a partir de Haploides seleccionados por supervivencia a bajas concentraciones de C02. Por E. Delgado y H. Medrano.-- Efecto de las poliaminas sobre la actividad fosfatasa ácida y ribonucleasa soluble en semillas de Garbanzo (Cicerarietinum L.). Por E. Merlo, T. Angosto y A. J. Matilla.-- Efectos de la 6-Bencil- aminopurina y el ácido Indol-3-Butfrico en cultivos in vitro de explantos de Hipocotilo-Epicotilo de Pinus canariensis Chr. Sm. ex DC. Por J. F. Pérez Francés, A. Bueno Marrero, V. M. García Díaz y R. Martín.-- Factores abióticos definitorios del área ocupada por Cytisus multiflorus (L 'Her) Sweet en España. Por E. V. Martínez Ropero, J. M. Gómez Gutiérrez y P. Galindo Villardon.-- Índice de satisfacción de los requerimientos hídricos de los cereales de invierno para una región marginal de secano. Por J. D. Paoloni.-- Effect of qualities of irrigation water and NPK fertilizars on grain and straw yield of wheat. Por R. Lal and P.Lal.-- Efecto de la concentración y tipo de agente solidificante del medio de cultivo en la vitrificación de brotes adventicios de Pinus canariensis. Por C. Martínez Pulido.-- Evolución de constituyentes químicos y de la emisión de etileno durante el desarrollo y maduración del albaricoque (Prunus armemízca, L. cv. Búlida). Por A. Amaros, M. Serrano, F. Riquelme y F. Romojaro.-- Cambio varietal en melocotoneros improductivos. Por J. Egea CaballeroPeer reviewe