Pub Date : 1998-12-14DOI: 10.1109/COMMAD.1998.791621
M. Attygalle, A. Nirmalathas, H. Liu, D. Novak
Subharmonic synchronous mode-locking (SSML) has been shown to be a very attractive scheme for achieving high repetition rate optical pulses at mm-wave frequencies, and beyond. In this paper, we report the dependence of the injected signal wavelength on the performance of SSML lasers around its lasing wavelengths. In particular, the effect of coherent interaction will be addressed.
{"title":"Injection signal wavelength dependence of a subharmonically synchronous mode-locked monolithic semiconductor laser","authors":"M. Attygalle, A. Nirmalathas, H. Liu, D. Novak","doi":"10.1109/COMMAD.1998.791621","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791621","url":null,"abstract":"Subharmonic synchronous mode-locking (SSML) has been shown to be a very attractive scheme for achieving high repetition rate optical pulses at mm-wave frequencies, and beyond. In this paper, we report the dependence of the injected signal wavelength on the performance of SSML lasers around its lasing wavelengths. In particular, the effect of coherent interaction will be addressed.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115304276","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 : 1998-12-14DOI: 10.1109/COMMAD.1998.791653
M. Wintrebert-Fouquet, D. Skellern
A large-signal model is presented for a Resonant Tunnelling Bipolar Transistor (RTBT) with a double barrier structure at the Emitter. These devices show large collector current peak-to-valley ratios (PVR) in the common-emitter transistor configuration because of significant current gain reduction beyond resonance. This large PVR makes them attractive devices for circuit applications, including high speed analog-to-digital converters. The model combines the Current-Voltage relationship for a Heterojunction Bipolar Transistor (HBT) and the Current-Voltage relationship for a Resonant Tunnelling Diode (RTD). The thermionic emission effects along the structure, across the RTD's barriers and across the HBT's heterojunction are taken into account. The HBT model is based on the extended Gummel and Poon model of Parikh and Lindholm which takes into account the current flow across the emitter-base and the base-collector heterojunctions. The RTD is modelled in the coherent tunnelling regime and incorporates thermionic effect regime. Model results are presented for a 3 /spl mu/m/spl times/3 /spl mu/m device published in the literature-an InGaAs/AlAs on InP resonant tunnelling heterojunction bipolar transistors.
{"title":"Large-signal model for a resonant heterojunction tunnelling transistor RTD(n)-p-n","authors":"M. Wintrebert-Fouquet, D. Skellern","doi":"10.1109/COMMAD.1998.791653","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791653","url":null,"abstract":"A large-signal model is presented for a Resonant Tunnelling Bipolar Transistor (RTBT) with a double barrier structure at the Emitter. These devices show large collector current peak-to-valley ratios (PVR) in the common-emitter transistor configuration because of significant current gain reduction beyond resonance. This large PVR makes them attractive devices for circuit applications, including high speed analog-to-digital converters. The model combines the Current-Voltage relationship for a Heterojunction Bipolar Transistor (HBT) and the Current-Voltage relationship for a Resonant Tunnelling Diode (RTD). The thermionic emission effects along the structure, across the RTD's barriers and across the HBT's heterojunction are taken into account. The HBT model is based on the extended Gummel and Poon model of Parikh and Lindholm which takes into account the current flow across the emitter-base and the base-collector heterojunctions. The RTD is modelled in the coherent tunnelling regime and incorporates thermionic effect regime. Model results are presented for a 3 /spl mu/m/spl times/3 /spl mu/m device published in the literature-an InGaAs/AlAs on InP resonant tunnelling heterojunction bipolar transistors.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117174128","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 : 1998-12-14DOI: 10.1109/COMMAD.1998.791676
D. Di Mola, L. Brioschi, A. Carrera, F. Fusari, M. Lenzi, G. Ongaro
The sputtering deposition technique has been used to realize nickel chromium thin films up to 12000 /spl Aring/ thick. The radio frequency biasing of the silica substrate has been implemented to control the film stress. Application of these films used as "heater electrodes" in thermo-optical devices has been reported.
{"title":"Unstressed nickel chromium thin films for thermo-optic application","authors":"D. Di Mola, L. Brioschi, A. Carrera, F. Fusari, M. Lenzi, G. Ongaro","doi":"10.1109/COMMAD.1998.791676","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791676","url":null,"abstract":"The sputtering deposition technique has been used to realize nickel chromium thin films up to 12000 /spl Aring/ thick. The radio frequency biasing of the silica substrate has been implemented to control the film stress. Application of these films used as \"heater electrodes\" in thermo-optical devices has been reported.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"248 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121129804","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 : 1998-12-14DOI: 10.1109/COMMAD.1998.791660
L. Dao, M. Johnston, M. Gal, L. Fu, H. Tan, C. Jagadish
Photoluminescence up conversion study of the intermixed InGaAs/GaAs and InGaAs/AlGaAs quantum wells showed that the capture of photo-excited carriers into the intermixed quantum wells is faster (25 ps) than capture into the non-intermixed quantum wells (45 ps). The reasons for this significant reduction in the capture time is related to modification of the shape of the intermixed quantum wells.
{"title":"Possibility of enhanced frequency response of intermixed InGaAs/GaAs and InGaAs/AlGaAs quantum well devices","authors":"L. Dao, M. Johnston, M. Gal, L. Fu, H. Tan, C. Jagadish","doi":"10.1109/COMMAD.1998.791660","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791660","url":null,"abstract":"Photoluminescence up conversion study of the intermixed InGaAs/GaAs and InGaAs/AlGaAs quantum wells showed that the capture of photo-excited carriers into the intermixed quantum wells is faster (25 ps) than capture into the non-intermixed quantum wells (45 ps). The reasons for this significant reduction in the capture time is related to modification of the shape of the intermixed quantum wells.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"5 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126130165","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 : 1998-12-14DOI: 10.1109/COMMAD.1998.791692
A. Micolich, R. P. Taylor, R. Newbury, J. Bird, Y. Aoyagi, T. Sugano
We present a study of fractal behaviour in the magneto-conductance fluctuations of semiconductor billiards as function of temperature. Non-zero temperatures introduce a finite phase coherence time and we find that this does not suppress fractal behaviour in the experimental data. Instead we show that the fractal dimension decreases with increasing temperature and present a remarkable similarity between the fractal dimension and the phase coherence time.
{"title":"The temperature dependent fractal dimension of magneto-conductance fluctuations in semiconductor billiards","authors":"A. Micolich, R. P. Taylor, R. Newbury, J. Bird, Y. Aoyagi, T. Sugano","doi":"10.1109/COMMAD.1998.791692","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791692","url":null,"abstract":"We present a study of fractal behaviour in the magneto-conductance fluctuations of semiconductor billiards as function of temperature. Non-zero temperatures introduce a finite phase coherence time and we find that this does not suppress fractal behaviour in the experimental data. Instead we show that the fractal dimension decreases with increasing temperature and present a remarkable similarity between the fractal dimension and the phase coherence time.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"23 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122396727","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 : 1998-12-14DOI: 10.1109/COMMAD.1998.791685
Yongxiang Li, J. Hagen, D. Haarer
Photocurrent of nanocrystalline TiO/sub 2/ thin films has been probed by using a steady-state photoconduction technique. A broad single peak (280-410 nm) photocurrent spectrum was observed for the TiO/sub 2/ thin films. The photocurrent maximum at about 360 nm associates with the direct band gap of anatase TiO/sub 2/. The electron-hole pair formation that occurs at the interface between semiconductor TiO/sub 2/ nanoparticles and a solution upon absorption of near UV light leads to redox reactions of solution species (W/sup +6//W/sup +5/). The mechanism of such photodriven processes are discussed along with the potential applications in photoelectrochemical cells and as particulate photochromic systems.
{"title":"W/sup +6//W/sup +5/ redox reactions at the interface of the nanocrystalline TiO/sub 2/ photoactive electrode","authors":"Yongxiang Li, J. Hagen, D. Haarer","doi":"10.1109/COMMAD.1998.791685","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791685","url":null,"abstract":"Photocurrent of nanocrystalline TiO/sub 2/ thin films has been probed by using a steady-state photoconduction technique. A broad single peak (280-410 nm) photocurrent spectrum was observed for the TiO/sub 2/ thin films. The photocurrent maximum at about 360 nm associates with the direct band gap of anatase TiO/sub 2/. The electron-hole pair formation that occurs at the interface between semiconductor TiO/sub 2/ nanoparticles and a solution upon absorption of near UV light leads to redox reactions of solution species (W/sup +6//W/sup +5/). The mechanism of such photodriven processes are discussed along with the potential applications in photoelectrochemical cells and as particulate photochromic systems.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117101680","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 : 1998-12-14DOI: 10.1109/COMMAD.1998.791696
D. Reilly, G. R. Facer, A. Dzurak, B. E. Kane, R. G. Clark, N. Lumpkin, L. Pfeiffer, K. West
The study of electron interaction effects in one dimensional transport requires heterostructures with ultra-low disorder. We have developed a novel GaAs/AlGaAs structure which avoids the random impurity potential present in conventional surface-gated HEMT devices by using epitaxially grown gates to produce an enhancement mode FET. Our quantum point contacts (QPCs) exhibit almost ideal conductance quantisation, however, below 2e/sup 2//h additional structure is observed. Such structure has also been seen in QPCs fabricated from ultra-high-mobility surface gated HEMTs and has been interpreted as evidence for a spin-correlated state. In our quantum wire devices this additional structure is further enhanced, indicating that the effective length of the 1D region may be a significant factor in determining the strength of correlation.
{"title":"Correlated electron phenomena in ultra-low-disorder quantum point contacts and quantum wires","authors":"D. Reilly, G. R. Facer, A. Dzurak, B. E. Kane, R. G. Clark, N. Lumpkin, L. Pfeiffer, K. West","doi":"10.1109/COMMAD.1998.791696","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791696","url":null,"abstract":"The study of electron interaction effects in one dimensional transport requires heterostructures with ultra-low disorder. We have developed a novel GaAs/AlGaAs structure which avoids the random impurity potential present in conventional surface-gated HEMT devices by using epitaxially grown gates to produce an enhancement mode FET. Our quantum point contacts (QPCs) exhibit almost ideal conductance quantisation, however, below 2e/sup 2//h additional structure is observed. Such structure has also been seen in QPCs fabricated from ultra-high-mobility surface gated HEMTs and has been interpreted as evidence for a spin-correlated state. In our quantum wire devices this additional structure is further enhanced, indicating that the effective length of the 1D region may be a significant factor in determining the strength of correlation.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129009240","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 : 1998-12-14DOI: 10.1109/COMMAD.1998.791689
Motlan, E. Goldys, K. Drozdowicz-Tomsia, T. Tansley
We examine the morphology of ultrathin GaSb layers grown by atmospheric pressure chemical vapour deposition on GaAs substrates. Atomic force microscopy is used as a primary characterisation tool. Growth experiments are carried out with V/III ratio and temperature optimised for growth of high quality GaSb. The effects of dilution rates of metalorganic precursors in hydrogen, and pulse growth durations are investigated as a means of controlling growth rate. Dilution rates used are up to forty times higher than those used for standard bulk growth, to enable longer and better controlled island growth. We have found the critical control parameters to be the dilution rate/deposition time ratio and the product of the same quantities. Minimum dimensions reproducibly obtained are about 100/spl times/80 nm at an island thickness of 5 nm, with densities controllable between 1 to 10/spl times/10/sup 13/ m/sup -2/. We relate these findings to the present theories of self-organised island growth and mention their relevance to composite structures for electronic and optoelectronic applications.
{"title":"Size and density control of MOCVD grown self-organised GaSb islands on GaAs","authors":"Motlan, E. Goldys, K. Drozdowicz-Tomsia, T. Tansley","doi":"10.1109/COMMAD.1998.791689","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791689","url":null,"abstract":"We examine the morphology of ultrathin GaSb layers grown by atmospheric pressure chemical vapour deposition on GaAs substrates. Atomic force microscopy is used as a primary characterisation tool. Growth experiments are carried out with V/III ratio and temperature optimised for growth of high quality GaSb. The effects of dilution rates of metalorganic precursors in hydrogen, and pulse growth durations are investigated as a means of controlling growth rate. Dilution rates used are up to forty times higher than those used for standard bulk growth, to enable longer and better controlled island growth. We have found the critical control parameters to be the dilution rate/deposition time ratio and the product of the same quantities. Minimum dimensions reproducibly obtained are about 100/spl times/80 nm at an island thickness of 5 nm, with densities controllable between 1 to 10/spl times/10/sup 13/ m/sup -2/. We relate these findings to the present theories of self-organised island growth and mention their relevance to composite structures for electronic and optoelectronic applications.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123649998","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 : 1998-12-14DOI: 10.1109/COMMAD.1998.791690
A. H. Ramelan, K. Drozdowicz-Tomsia, T. Tansley
A study of structural, electrical and optical properties of GaSb and Al/sub x/Ga/sub 1-x/Sb (0.05/spl les/x/spl les/0.25) grown by metalorganic chemical vapour deposition on GaAs, GaSb and Ge substrates using TMAl, TMGa, and TMSb is reported. The optimum growth window established for GaSb growth (temperature 540/spl deg/C and V/III=0.72) is significantly different from optimal growth parameters for AlGaSb layers. Higher V/III ratios and higher temperatures are required to protect the surface morphology of AlGaSb. All Al/sub x/Ga/sub 1-x/Sb in the investigated composition range 0.05/spl les/x/spl les/0.25 were grown at 580/spl deg/C and 800/spl deg/C and V/III ratio=3 and are characterized by excellent, smooth morphology, very high optical transmission and electrical parameters comparable with the best reported for this type of layer.
{"title":"Growth and properties of GaSb and Al/sub x/Ga/sub 1-x/Sb layers by MOCVD","authors":"A. H. Ramelan, K. Drozdowicz-Tomsia, T. Tansley","doi":"10.1109/COMMAD.1998.791690","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791690","url":null,"abstract":"A study of structural, electrical and optical properties of GaSb and Al/sub x/Ga/sub 1-x/Sb (0.05/spl les/x/spl les/0.25) grown by metalorganic chemical vapour deposition on GaAs, GaSb and Ge substrates using TMAl, TMGa, and TMSb is reported. The optimum growth window established for GaSb growth (temperature 540/spl deg/C and V/III=0.72) is significantly different from optimal growth parameters for AlGaSb layers. Higher V/III ratios and higher temperatures are required to protect the surface morphology of AlGaSb. All Al/sub x/Ga/sub 1-x/Sb in the investigated composition range 0.05/spl les/x/spl les/0.25 were grown at 580/spl deg/C and 800/spl deg/C and V/III ratio=3 and are characterized by excellent, smooth morphology, very high optical transmission and electrical parameters comparable with the best reported for this type of layer.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123670480","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 : 1998-12-14DOI: 10.1109/COMMAD.1998.791630
W. Liu, Y. Shie, W. Chang, S. Feng, K. Yu, J. Yan
In this letter, a new InGaP/GaAs superlattice-emitter resonant tunneling bipolar transistor (SE-RTBT) is fabricated and demonstrated. A 5-period InGaP/GaAs superlattice is used to serve the RT route and the confinement barrier for minority carriers. Due to the large valence band discontinuity (/spl Delta/E/sub V/) at the InGaP/GaAs heterointerface, a high current gain (/spl beta//sub max//spl sime/220) is obtained. Furthermore, the interesting N-shaped negative-differential-resistance (NDR) phenomena resulting from RT effect are found both in the saturation and forward-active region of the current-voltage characteristics at room temperature.
{"title":"InGaP/GaAs resonant-tunneling transistor (RTT)","authors":"W. Liu, Y. Shie, W. Chang, S. Feng, K. Yu, J. Yan","doi":"10.1109/COMMAD.1998.791630","DOIUrl":"https://doi.org/10.1109/COMMAD.1998.791630","url":null,"abstract":"In this letter, a new InGaP/GaAs superlattice-emitter resonant tunneling bipolar transistor (SE-RTBT) is fabricated and demonstrated. A 5-period InGaP/GaAs superlattice is used to serve the RT route and the confinement barrier for minority carriers. Due to the large valence band discontinuity (/spl Delta/E/sub V/) at the InGaP/GaAs heterointerface, a high current gain (/spl beta//sub max//spl sime/220) is obtained. Furthermore, the interesting N-shaped negative-differential-resistance (NDR) phenomena resulting from RT effect are found both in the saturation and forward-active region of the current-voltage characteristics at room temperature.","PeriodicalId":300064,"journal":{"name":"1998 Conference on Optoelectronic and Microelectronic Materials and Devices. Proceedings (Cat. No.98EX140)","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114219563","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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