Pub Date : 2013-03-21DOI: 10.1109/CDE.2013.6481336
A. Benali, F. Traversa, G. Albareda, X. Oriols, M. Aghoutane
The improvement of the intrinsic high-frequency performance of emerging transistors is commonly based on reducing electron transit time and it is pursued by either reducing the channel length or employing novel high-electron-mobility materials. For gate-all-around transistors with lateral dimensions much shorter than their length, a careful analysis of the total time-dependent current shows that a time shorter than the electron transit time along the channel controls their high-frequency behavior. Both, the standard displacement current definition and the Ramo-Shockley-Pellegrini theorem are used to demonstrate this effect. Therefore, the high-frequency performance of such transistors, with a proper geometry design, can go beyond the intrinsic limits imposed by the electron transit time.
{"title":"Towards frequency performance improvement of emerging devices without length scaling","authors":"A. Benali, F. Traversa, G. Albareda, X. Oriols, M. Aghoutane","doi":"10.1109/CDE.2013.6481336","DOIUrl":"https://doi.org/10.1109/CDE.2013.6481336","url":null,"abstract":"The improvement of the intrinsic high-frequency performance of emerging transistors is commonly based on reducing electron transit time and it is pursued by either reducing the channel length or employing novel high-electron-mobility materials. For gate-all-around transistors with lateral dimensions much shorter than their length, a careful analysis of the total time-dependent current shows that a time shorter than the electron transit time along the channel controls their high-frequency behavior. Both, the standard displacement current definition and the Ramo-Shockley-Pellegrini theorem are used to demonstrate this effect. Therefore, the high-frequency performance of such transistors, with a proper geometry design, can go beyond the intrinsic limits imposed by the electron transit time.","PeriodicalId":6614,"journal":{"name":"2013 Spanish Conference on Electron Devices","volume":"35 4 1","pages":"37-40"},"PeriodicalIF":0.0,"publicationDate":"2013-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90460208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-03-21DOI: 10.1109/CDE.2013.6481368
M. Avila, M. Estrada, A. Cerdeira, L. Reséndiz
Poly(9, 9-dioctylfluorene-co-Bithiophene) (F8T2) is used for the fabrication of p-type Polymeric Thin-Film Transistors (PTFT's), which can show high Ion/Ioff ratio in the transfer characteristics. In this work the Active Saturated Load Inverter (ASLI), fabricated with Poly (methyl methacrylate) (PMMA) as the dielectric film and F8T2 as the active semiconductor PTFTs, is analyzed and simulated using SmartSpice, where a compact model, UMEM, previously developed by our group was included. Specifics of the AC measurements of these devices are discussed.
{"title":"DC and AC characterization of PTFT inverters using Poly(9, 9-dioctylfluorene-co-Bithiophene) (F8T2)","authors":"M. Avila, M. Estrada, A. Cerdeira, L. Reséndiz","doi":"10.1109/CDE.2013.6481368","DOIUrl":"https://doi.org/10.1109/CDE.2013.6481368","url":null,"abstract":"Poly(9, 9-dioctylfluorene-co-Bithiophene) (F8T2) is used for the fabrication of p-type Polymeric Thin-Film Transistors (PTFT's), which can show high Ion/Ioff ratio in the transfer characteristics. In this work the Active Saturated Load Inverter (ASLI), fabricated with Poly (methyl methacrylate) (PMMA) as the dielectric film and F8T2 as the active semiconductor PTFTs, is analyzed and simulated using SmartSpice, where a compact model, UMEM, previously developed by our group was included. Specifics of the AC measurements of these devices are discussed.","PeriodicalId":6614,"journal":{"name":"2013 Spanish Conference on Electron Devices","volume":"52 1","pages":"163-166"},"PeriodicalIF":0.0,"publicationDate":"2013-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91144263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-03-21DOI: 10.1109/CDE.2013.6481414
E. Perez, M. Maestro, H. García, H. Castán, S. Dueñas, L. Bailón
In order to find the regions in solar cells where the efficiency drops an experimental setup is tuned up. Through this equipment a set of samples are characterized checking that its response is the expected. The photocurrent maps obtained allow us to determine the regions with higher defects concentration. These regions will be characterized using electrical techniques which will give us additional information of the nature of these defects.
{"title":"Photocurrent measurements for solar cells characterization","authors":"E. Perez, M. Maestro, H. García, H. Castán, S. Dueñas, L. Bailón","doi":"10.1109/CDE.2013.6481414","DOIUrl":"https://doi.org/10.1109/CDE.2013.6481414","url":null,"abstract":"In order to find the regions in solar cells where the efficiency drops an experimental setup is tuned up. Through this equipment a set of samples are characterized checking that its response is the expected. The photocurrent maps obtained allow us to determine the regions with higher defects concentration. These regions will be characterized using electrical techniques which will give us additional information of the nature of these defects.","PeriodicalId":6614,"journal":{"name":"2013 Spanish Conference on Electron Devices","volume":"21 1","pages":"349-352"},"PeriodicalIF":0.0,"publicationDate":"2013-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86987605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-03-21DOI: 10.1109/CDE.2013.6481398
H. García, H. Castán, S. Dueñas, L. Bailón, P. C. Feijoo, M. Pampillón, E. Andrés
The electrical properties of ScO-based MIS structures have been electrically studied. The high-k films were deposited by high pressure sputtering (HPS). Aluminum and Ti were used as gate electrodes. Defects inside the oxide seem to be reduced when increasing the chamber pressure. However, leakage current density increases in this case.
{"title":"Electrical study of ScO-based MIS structures using Al and Ti as gate electrodes","authors":"H. García, H. Castán, S. Dueñas, L. Bailón, P. C. Feijoo, M. Pampillón, E. Andrés","doi":"10.1109/CDE.2013.6481398","DOIUrl":"https://doi.org/10.1109/CDE.2013.6481398","url":null,"abstract":"The electrical properties of ScO-based MIS structures have been electrically studied. The high-k films were deposited by high pressure sputtering (HPS). Aluminum and Ti were used as gate electrodes. Defects inside the oxide seem to be reduced when increasing the chamber pressure. However, leakage current density increases in this case.","PeriodicalId":6614,"journal":{"name":"2013 Spanish Conference on Electron Devices","volume":"20 1","pages":"285-288"},"PeriodicalIF":0.0,"publicationDate":"2013-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84635741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-03-21DOI: 10.1109/CDE.2013.6481335
J. Banqueri, M. Carvajal, A. Palma
In this paper, the advances in the modeling of the radiation effects in MOSFETs will be briefly exposed. The change of the threshold voltage, mobility, subthreshold swing and the low frequency noise with the ionizing radiation will be shown and, if possible, modeled. Finally, the use of the MOSFET as dosimeter, mainly for clinical use, will be detailed, where our contribution in the readout techniques will be detailed in order to obtain a low-cost high performance dosimetric verification system.
{"title":"Modeling of radiation effects in MOSFETs","authors":"J. Banqueri, M. Carvajal, A. Palma","doi":"10.1109/CDE.2013.6481335","DOIUrl":"https://doi.org/10.1109/CDE.2013.6481335","url":null,"abstract":"In this paper, the advances in the modeling of the radiation effects in MOSFETs will be briefly exposed. The change of the threshold voltage, mobility, subthreshold swing and the low frequency noise with the ionizing radiation will be shown and, if possible, modeled. Finally, the use of the MOSFET as dosimeter, mainly for clinical use, will be detailed, where our contribution in the readout techniques will be detailed in order to obtain a low-cost high performance dosimetric verification system.","PeriodicalId":6614,"journal":{"name":"2013 Spanish Conference on Electron Devices","volume":"39 1","pages":"33-36"},"PeriodicalIF":0.0,"publicationDate":"2013-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89333718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-03-21DOI: 10.1109/CDE.2013.6481407
G. del Pozo, B. Romero, B. Arredondo
In this work we have fabricated and characterized organic solar cells (OSC) based on blends of polyhexylthiophene (P3HT) and [6,6]-phenil-C61-butyric acid methyl ester (PCBM) with two different cathodes: Al and LiF/Al. Current- Voltage (I-V) curves under illumination have been measured and fitted with the standard equivalent circuit in order to extract circuital parameters, such as series and parallel resistances (Rs and Rp) ideality factor (n) and inverse saturation current (I0). The introduction of a thin layer (0.5 nm) of LiF between active layer and Al increases the open circuit voltage (Voc) but slightly reduces short current (Isc) and fill factor (FF). The overall result is a slight increase of the efficiency, from 2.53 % to 2.57 %. Circuital parameters have been extracted with two methods (approximated an exact), and results show that structures with LiF layer have lower parasitic effects (lower Rs and higher Rp).
{"title":"Influence of cathode in organic solar cells performance","authors":"G. del Pozo, B. Romero, B. Arredondo","doi":"10.1109/CDE.2013.6481407","DOIUrl":"https://doi.org/10.1109/CDE.2013.6481407","url":null,"abstract":"In this work we have fabricated and characterized organic solar cells (OSC) based on blends of polyhexylthiophene (P3HT) and [6,6]-phenil-C61-butyric acid methyl ester (PCBM) with two different cathodes: Al and LiF/Al. Current- Voltage (I-V) curves under illumination have been measured and fitted with the standard equivalent circuit in order to extract circuital parameters, such as series and parallel resistances (Rs and Rp) ideality factor (n) and inverse saturation current (I0). The introduction of a thin layer (0.5 nm) of LiF between active layer and Al increases the open circuit voltage (Voc) but slightly reduces short current (Isc) and fill factor (FF). The overall result is a slight increase of the efficiency, from 2.53 % to 2.57 %. Circuital parameters have been extracted with two methods (approximated an exact), and results show that structures with LiF layer have lower parasitic effects (lower Rs and higher Rp).","PeriodicalId":6614,"journal":{"name":"2013 Spanish Conference on Electron Devices","volume":"24 1","pages":"321-324"},"PeriodicalIF":0.0,"publicationDate":"2013-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74429008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-03-21DOI: 10.1109/CDE.2013.6481362
N. J. Divins, E. López, J. Llorca, D. Vega, A. Rodríguez, F. G. de Rivera, I. Angurell, M. Rossell
A macroporous silicon micromonolith containing ca. 40,000 regular channels of 3.3 μm in diameter per square millimeter has been successfully functionalized with an Au/TiO2 catalyst for CO preferential oxidation (CO-PrOx) in the presence of hydrogen. The functionalization of the silicon microchannels has been accomplished by growing a SiO2 layer on the channel walls, followed by exchange with a titanium alkoxyde precursor and decomposition into TiO2 and, finally, by anchoring carbosilanethiol dendron protected pre-formed Au nanoparticles. Catalytically active centers at the Au-TiO2 interface have been obtained by thermal activation. With this method, an excellent homogeneity and adherence of the catalytic layer over the microchannels of the macroporous silicon micromonolith has been obtained, which has been tested for CO-PrOx at 363-433 K and λ=2 under H2/CO=0-20 (molar). The macroporous silicon micromonolith converts ca. 3 NmL of CO per minute and mL of micro reactor at 433 K under H2/CO=20, suggesting that it could be particularly effective for hydrogen purification in low-temperature microfuel cells for portable applications.
{"title":"Macroporous silicon microreactor for the preferential oxidation of CO","authors":"N. J. Divins, E. López, J. Llorca, D. Vega, A. Rodríguez, F. G. de Rivera, I. Angurell, M. Rossell","doi":"10.1109/CDE.2013.6481362","DOIUrl":"https://doi.org/10.1109/CDE.2013.6481362","url":null,"abstract":"A macroporous silicon micromonolith containing ca. 40,000 regular channels of 3.3 μm in diameter per square millimeter has been successfully functionalized with an Au/TiO2 catalyst for CO preferential oxidation (CO-PrOx) in the presence of hydrogen. The functionalization of the silicon microchannels has been accomplished by growing a SiO2 layer on the channel walls, followed by exchange with a titanium alkoxyde precursor and decomposition into TiO2 and, finally, by anchoring carbosilanethiol dendron protected pre-formed Au nanoparticles. Catalytically active centers at the Au-TiO2 interface have been obtained by thermal activation. With this method, an excellent homogeneity and adherence of the catalytic layer over the microchannels of the macroporous silicon micromonolith has been obtained, which has been tested for CO-PrOx at 363-433 K and λ=2 under H2/CO=0-20 (molar). The macroporous silicon micromonolith converts ca. 3 NmL of CO per minute and mL of micro reactor at 433 K under H2/CO=20, suggesting that it could be particularly effective for hydrogen purification in low-temperature microfuel cells for portable applications.","PeriodicalId":6614,"journal":{"name":"2013 Spanish Conference on Electron Devices","volume":"3 1","pages":"139-142"},"PeriodicalIF":0.0,"publicationDate":"2013-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73162348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-03-21DOI: 10.1109/CDE.2013.6481378
A. Coll, S. Bermejo, L. Castañer
Nanostructuring materials such as silicon provides a good technology to fabricate optical and sensing devices. The possibility to fill the pores or channels with different material opens the way to new applications. In this work, we study the electrokinetics of electrospraying technique to fill porous material with nanobeads. The simulations take into account a photonic crystal topology applying a difference potential of 14 kV. Measurements show the viability of filling alumina nanoporous with 360nm polyestyrene nanospheres.
{"title":"Nanohole particle filling by electrospray","authors":"A. Coll, S. Bermejo, L. Castañer","doi":"10.1109/CDE.2013.6481378","DOIUrl":"https://doi.org/10.1109/CDE.2013.6481378","url":null,"abstract":"Nanostructuring materials such as silicon provides a good technology to fabricate optical and sensing devices. The possibility to fill the pores or channels with different material opens the way to new applications. In this work, we study the electrokinetics of electrospraying technique to fill porous material with nanobeads. The simulations take into account a photonic crystal topology applying a difference potential of 14 kV. Measurements show the viability of filling alumina nanoporous with 360nm polyestyrene nanospheres.","PeriodicalId":6614,"journal":{"name":"2013 Spanish Conference on Electron Devices","volume":"98 1","pages":"203-206"},"PeriodicalIF":0.0,"publicationDate":"2013-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73605955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-03-21DOI: 10.1109/CDE.2013.6481399
P. Otero, C. Alberte, J. Rodríguez, M. Vetter, J. Andreu
Analysis of continuously acquired electrical data of amorphous silicon (a-Si) modules working under ambient conditions enable us to separate the effects of various factors, as e.g, module temperature, sun spectrum, ambient temperature, influencing a-Si module performance. This results in an improved understanding of the seasonal fluctuations of electric characteristics that can be expected in different ambient conditions. For the test site of Orense, seasonal oscillations lead to electrical power variation of 19% (± 9.5%) around an annual average value with a minimum around January and a maximum around mid of July. Variation of the sun spectrum has the highest impact on the outdoor performance of a-Si modules with amplitude corresponding to about 5.5%. The Staebler Wronski effect has a slightly lower influence with amplitude of about 4 %.
{"title":"Investigation of seasonal fluctuation of electrical parameters of amorphous silicon modules in ambient conditions","authors":"P. Otero, C. Alberte, J. Rodríguez, M. Vetter, J. Andreu","doi":"10.1109/CDE.2013.6481399","DOIUrl":"https://doi.org/10.1109/CDE.2013.6481399","url":null,"abstract":"Analysis of continuously acquired electrical data of amorphous silicon (a-Si) modules working under ambient conditions enable us to separate the effects of various factors, as e.g, module temperature, sun spectrum, ambient temperature, influencing a-Si module performance. This results in an improved understanding of the seasonal fluctuations of electric characteristics that can be expected in different ambient conditions. For the test site of Orense, seasonal oscillations lead to electrical power variation of 19% (± 9.5%) around an annual average value with a minimum around January and a maximum around mid of July. Variation of the sun spectrum has the highest impact on the outdoor performance of a-Si modules with amplitude corresponding to about 5.5%. The Staebler Wronski effect has a slightly lower influence with amplitude of about 4 %.","PeriodicalId":6614,"journal":{"name":"2013 Spanish Conference on Electron Devices","volume":"55 1","pages":"289-292"},"PeriodicalIF":0.0,"publicationDate":"2013-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76591152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-03-21DOI: 10.1109/CDE.2013.6481363
D. Vega, J. Reina, A. Rodríguez
In this paper we study a compact gas sensor based on a photonic crystal built from macroporous silicon. Its sensing mechanism is based in the absorption of infrared light by a gas. Photonic crystals are structured materials which can be engineered to have photonic bandgaps. They also can be tailored to create localized states inside the bandgaps. We exploit the possibility to confine light inside a cavity with very high-Q, which allows for long interaction time between the gas and light. Simulation of different 2-D and 3-D structures have been done to extract the appropriate dimensions for gas detection, and their optical behaviour. Resonant cavities were created by adding defects in the ordered geometrical structure, thus creating a single state and confining the trapped light in a crystal bandgap. The structures were tested by simulating the presence of ethanol inside the structures. Gas is to be detected by a noticeable change in the resonance peak both in amplitude and spread, caused by the gas detuning the cavity. Macroporous silicon samples of the investigated structures with defects were fabricated and measured by IR spectrography. Cavity resonances can be clearly seen in the samples, though we need to improve fabrication to adjust the theoretically calculated dimensions.
{"title":"Macroporous silicon photonic crystals for gas sensing","authors":"D. Vega, J. Reina, A. Rodríguez","doi":"10.1109/CDE.2013.6481363","DOIUrl":"https://doi.org/10.1109/CDE.2013.6481363","url":null,"abstract":"In this paper we study a compact gas sensor based on a photonic crystal built from macroporous silicon. Its sensing mechanism is based in the absorption of infrared light by a gas. Photonic crystals are structured materials which can be engineered to have photonic bandgaps. They also can be tailored to create localized states inside the bandgaps. We exploit the possibility to confine light inside a cavity with very high-Q, which allows for long interaction time between the gas and light. Simulation of different 2-D and 3-D structures have been done to extract the appropriate dimensions for gas detection, and their optical behaviour. Resonant cavities were created by adding defects in the ordered geometrical structure, thus creating a single state and confining the trapped light in a crystal bandgap. The structures were tested by simulating the presence of ethanol inside the structures. Gas is to be detected by a noticeable change in the resonance peak both in amplitude and spread, caused by the gas detuning the cavity. Macroporous silicon samples of the investigated structures with defects were fabricated and measured by IR spectrography. Cavity resonances can be clearly seen in the samples, though we need to improve fabrication to adjust the theoretically calculated dimensions.","PeriodicalId":6614,"journal":{"name":"2013 Spanish Conference on Electron Devices","volume":"6 1","pages":"143-146"},"PeriodicalIF":0.0,"publicationDate":"2013-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77955410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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