Pub Date : 1995-11-27DOI: 10.1109/EDMO.1995.493696
S. Plimmer, J. David, T. Lee, G. Rees, P. Houston, P. Robson, R. Grey, D. Herbert, A. Higgs, D. Wight
Electron and hole multiplication characteristics have been measured on a series of GaAs p-i-n and n-i-p diodes in which the nominal i-region thicknesses, w, range from 1 /spl mu/m to 25 nm. Using the conventional analysis, where ionization is assumed to be uniform across the device, the effective electron and hole ionization coefficients (/spl alpha/ and /spl beta/ respectively) have been deduced. The results obtained from the w=1 /spl mu/m and 0.5 /spl mu/m structures agree with published data which was derived from thick devices. However, those observed in the thinner structures show device width dependence. By implementing semi-analytical techniques to solve Boltzmann's equation and to interpret these results, dead space effects are seen to reduce /spl alpha/ and /spl beta/ in short devices at low multiplication values but overshoot effects compensate when the electric field is increased.
{"title":"Non-local effects on the multiplication characteristics of thin GaAs p-i-n and n-i-p diodes","authors":"S. Plimmer, J. David, T. Lee, G. Rees, P. Houston, P. Robson, R. Grey, D. Herbert, A. Higgs, D. Wight","doi":"10.1109/EDMO.1995.493696","DOIUrl":"https://doi.org/10.1109/EDMO.1995.493696","url":null,"abstract":"Electron and hole multiplication characteristics have been measured on a series of GaAs p-i-n and n-i-p diodes in which the nominal i-region thicknesses, w, range from 1 /spl mu/m to 25 nm. Using the conventional analysis, where ionization is assumed to be uniform across the device, the effective electron and hole ionization coefficients (/spl alpha/ and /spl beta/ respectively) have been deduced. The results obtained from the w=1 /spl mu/m and 0.5 /spl mu/m structures agree with published data which was derived from thick devices. However, those observed in the thinner structures show device width dependence. By implementing semi-analytical techniques to solve Boltzmann's equation and to interpret these results, dead space effects are seen to reduce /spl alpha/ and /spl beta/ in short devices at low multiplication values but overshoot effects compensate when the electric field is increased.","PeriodicalId":431745,"journal":{"name":"Proceedings of the 3rd IEEE International Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications, EDMO 95","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115344680","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 : 1995-11-27DOI: 10.1109/EDMO.1995.493712
M. Schefer, U. Lott, B. Klepser, H. Meier, W. Patrick, W. Bachtold
The design, fabrication, and the measured results of V-band monolithically integrated fundamental oscillators are presented. The active device is a 0.2 /spl mu/m InP based HEMT with f/sub max/=200 GHz and f/sub t/=100 GHz. A basic V-band oscillator, a high power and a varactor tuned oscillator are compared. The resonance frequency of the basic oscillator is 54.333 GHz and the phase noise -70 dBc/Hz @ 1 MHz offset. The high power oscillator shows 83 dBm output power at 48 GHz For the varactor tunable oscillator an output power of 0 dBm at 63 GHz and a tuning range of 100 MHz are measured. The circuits were fabricated in coplanar technology.
{"title":"Monolithic V-band high power and varactor tunable HEMT oscillators","authors":"M. Schefer, U. Lott, B. Klepser, H. Meier, W. Patrick, W. Bachtold","doi":"10.1109/EDMO.1995.493712","DOIUrl":"https://doi.org/10.1109/EDMO.1995.493712","url":null,"abstract":"The design, fabrication, and the measured results of V-band monolithically integrated fundamental oscillators are presented. The active device is a 0.2 /spl mu/m InP based HEMT with f/sub max/=200 GHz and f/sub t/=100 GHz. A basic V-band oscillator, a high power and a varactor tuned oscillator are compared. The resonance frequency of the basic oscillator is 54.333 GHz and the phase noise -70 dBc/Hz @ 1 MHz offset. The high power oscillator shows 83 dBm output power at 48 GHz For the varactor tunable oscillator an output power of 0 dBm at 63 GHz and a tuning range of 100 MHz are measured. The circuits were fabricated in coplanar technology.","PeriodicalId":431745,"journal":{"name":"Proceedings of the 3rd IEEE International Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications, EDMO 95","volume":"136 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121952182","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 : 1995-11-27DOI: 10.1109/EDMO.1995.493709
G. Meneghesso, E. De Bortoli, P. Cova, R. Menozzi
AlGaAs/InGaAs pseudomorphic HEMTs (PM-HEMTs) have been submitted to either hot electron or high temperature storage stress tests, A non-permanent increase of the drain current is observed after the tests and is correlated with the presence of deep levels in the devices, Trapping of holes generated by impact ionization (during the hot electron stress) or thermally activated electron detrapping (during the high temperature storage) are responsible for the observed shifts of the PM-HEMT's characteristics. We also present a new DC based investigation technique that gives information about the localization of the trapped/detrapped charge.
{"title":"On temperature and hot electron induced degradation in AlGaAs/InGaAs PM-HEMT's","authors":"G. Meneghesso, E. De Bortoli, P. Cova, R. Menozzi","doi":"10.1109/EDMO.1995.493709","DOIUrl":"https://doi.org/10.1109/EDMO.1995.493709","url":null,"abstract":"AlGaAs/InGaAs pseudomorphic HEMTs (PM-HEMTs) have been submitted to either hot electron or high temperature storage stress tests, A non-permanent increase of the drain current is observed after the tests and is correlated with the presence of deep levels in the devices, Trapping of holes generated by impact ionization (during the hot electron stress) or thermally activated electron detrapping (during the high temperature storage) are responsible for the observed shifts of the PM-HEMT's characteristics. We also present a new DC based investigation technique that gives information about the localization of the trapped/detrapped charge.","PeriodicalId":431745,"journal":{"name":"Proceedings of the 3rd IEEE International Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications, EDMO 95","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126168730","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 : 1995-11-27DOI: 10.1109/EDMO.1995.493706
G. Passiopoulos, D. Webster, A. Parker, D. Haigh
In this paper we investigate the effect of bias conditions and load resistance on the nonlinear behaviour of a MESFET Common Source (CS) amplifier at medium frequencies. The distortion nulling effects observed in measured results provide a good criteria for assessing large signal model performance over a wide range of bias conditions. The Parker-Skellern model of the MESFET is used to simulate the MESFET circuit configuration for which the distortion measurements were performed. The model predicts the observed distortion structure.
{"title":"Nonlinear common source MESFET behaviour and model validation","authors":"G. Passiopoulos, D. Webster, A. Parker, D. Haigh","doi":"10.1109/EDMO.1995.493706","DOIUrl":"https://doi.org/10.1109/EDMO.1995.493706","url":null,"abstract":"In this paper we investigate the effect of bias conditions and load resistance on the nonlinear behaviour of a MESFET Common Source (CS) amplifier at medium frequencies. The distortion nulling effects observed in measured results provide a good criteria for assessing large signal model performance over a wide range of bias conditions. The Parker-Skellern model of the MESFET is used to simulate the MESFET circuit configuration for which the distortion measurements were performed. The model predicts the observed distortion structure.","PeriodicalId":431745,"journal":{"name":"Proceedings of the 3rd IEEE International Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications, EDMO 95","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123050998","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 : 1995-11-27DOI: 10.1109/EDMO.1995.493684
V. A. Wilkinson, M. Kelly
A plethora of new device concepts have been established that exploit quantum confinement or tunnelling in semiconductor multilayers as the basis of their operation, and some device prototypes have given impressive performance figures-of-merit. These devices will never become commercial, however, until there is some confidence in designing to an I-V characteristic, and being able to grow and qualify the semiconductor multilayers with adequate confidence to undertake reverse engineering. A summary of tunnel device ideas is followed by a description of a project to determine whether even the simplest tunnel structure (a single tunnel barrier in an asymmetric doping environment-the ASPAT diode) can be considered manufacturable.
{"title":"Manufacturability of quantum semiconductor devices","authors":"V. A. Wilkinson, M. Kelly","doi":"10.1109/EDMO.1995.493684","DOIUrl":"https://doi.org/10.1109/EDMO.1995.493684","url":null,"abstract":"A plethora of new device concepts have been established that exploit quantum confinement or tunnelling in semiconductor multilayers as the basis of their operation, and some device prototypes have given impressive performance figures-of-merit. These devices will never become commercial, however, until there is some confidence in designing to an I-V characteristic, and being able to grow and qualify the semiconductor multilayers with adequate confidence to undertake reverse engineering. A summary of tunnel device ideas is followed by a description of a project to determine whether even the simplest tunnel structure (a single tunnel barrier in an asymmetric doping environment-the ASPAT diode) can be considered manufacturable.","PeriodicalId":431745,"journal":{"name":"Proceedings of the 3rd IEEE International Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications, EDMO 95","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125314142","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 : 1995-11-27DOI: 10.1109/EDMO.1995.493687
J.J. Harris, J. M. Roberts, R. Jaszek, M. Hopkinson
We report the use of strain-balanced quantum well structures to generate high carrier density, high mobility layers suitable for power FET applications. Current designs of modulation-doped heterojunctions (i.e. HEMTs) have a sheet carrier density limited to a maximum of /spl sim/3/spl times/10/sup 12/ cm/sup -2/, while doped channel devices (HFETs) allow higher densities, but with degraded mobility. We have investigated two techniques for giving improved properties, (a) strain-balanced AlAs/InAs/AlAs HEMTs grown on InP, where sheet densities of /spl sim/10/sup 13/ cm/sup -2/ have been generated, although with some evidence of mobility degradation, and (b) delta-doped, compositionally graded HFETs, again strain-balanced on InP, where excellent mobilities and saturation drift velocities have been obtained for sheet densities of 4-5/spl times/10/sup 12/ cm/sup -2/. This paper describes the growth techniques used to produce these samples, and presents the X-ray diffraction data and electrical properties of the layers.
{"title":"Strain-balanced quantum wells for power FET applications","authors":"J.J. Harris, J. M. Roberts, R. Jaszek, M. Hopkinson","doi":"10.1109/EDMO.1995.493687","DOIUrl":"https://doi.org/10.1109/EDMO.1995.493687","url":null,"abstract":"We report the use of strain-balanced quantum well structures to generate high carrier density, high mobility layers suitable for power FET applications. Current designs of modulation-doped heterojunctions (i.e. HEMTs) have a sheet carrier density limited to a maximum of /spl sim/3/spl times/10/sup 12/ cm/sup -2/, while doped channel devices (HFETs) allow higher densities, but with degraded mobility. We have investigated two techniques for giving improved properties, (a) strain-balanced AlAs/InAs/AlAs HEMTs grown on InP, where sheet densities of /spl sim/10/sup 13/ cm/sup -2/ have been generated, although with some evidence of mobility degradation, and (b) delta-doped, compositionally graded HFETs, again strain-balanced on InP, where excellent mobilities and saturation drift velocities have been obtained for sheet densities of 4-5/spl times/10/sup 12/ cm/sup -2/. This paper describes the growth techniques used to produce these samples, and presents the X-ray diffraction data and electrical properties of the layers.","PeriodicalId":431745,"journal":{"name":"Proceedings of the 3rd IEEE International Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications, EDMO 95","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114307269","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 : 1995-11-27DOI: 10.1109/EDMO.1995.493702
P. Cova, R. Menozzi, D. Lacey, Y. Baeyens, F. Fantini
This paper reports on hot electron stress experiments performed on 0.25 /spl mu/m AlGaAs/InGaAs/GaAs pseudomorphic HEMTs. Devices have been subjected to high drain bias stress cycles with drain voltages ranging between 5 and 8 V up to a cumulative stress time of 18 hours. The effect of the stress on the device DC characteristics is studied. In particular, stressed devices show an increase of the gate-drain breakdown voltage (breakdown walkout) and changes of the drain current in the saturation region that depend, both in magnitude and polarity, on the stress conditions: moderate stress bias and time yield an increase of the drain current, whereas more severe conditions tend to lower it.
本文报道了在0.25 /spl μ m AlGaAs/InGaAs/GaAs伪晶HEMTs上进行的热电子应力实验。器件承受高漏极偏置应力循环，漏极电压范围在5到8 V之间，累积应力时间为18小时。研究了应力对器件直流特性的影响。特别是，受应力的器件表现出栅极-漏极击穿电压(击穿失效)的增加和饱和区域漏极电流的变化，这取决于应力条件的大小和极性:适度的应力偏置和时间会产生漏极电流的增加，而更严重的条件往往会降低漏极电流。
{"title":"Hot electron degradation effects in Al/sub 0.25/Ga/sub 0.75/As/In/sub 0.2/Ga/sub 0.8/As/GaAs PHEMTs","authors":"P. Cova, R. Menozzi, D. Lacey, Y. Baeyens, F. Fantini","doi":"10.1109/EDMO.1995.493702","DOIUrl":"https://doi.org/10.1109/EDMO.1995.493702","url":null,"abstract":"This paper reports on hot electron stress experiments performed on 0.25 /spl mu/m AlGaAs/InGaAs/GaAs pseudomorphic HEMTs. Devices have been subjected to high drain bias stress cycles with drain voltages ranging between 5 and 8 V up to a cumulative stress time of 18 hours. The effect of the stress on the device DC characteristics is studied. In particular, stressed devices show an increase of the gate-drain breakdown voltage (breakdown walkout) and changes of the drain current in the saturation region that depend, both in magnitude and polarity, on the stress conditions: moderate stress bias and time yield an increase of the drain current, whereas more severe conditions tend to lower it.","PeriodicalId":431745,"journal":{"name":"Proceedings of the 3rd IEEE International Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications, EDMO 95","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123181861","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 : 1995-11-27DOI: 10.1109/EDMO.1995.493700
D. Kozlowski, J. Young, J. England, R. Plumb
Localised reflections within the lasing filament of Fabry-Perot lasers cause spectral perturbations. Focused Ga/sup +/ ion beam etching can be used to form steep walled pits of submicron size in the lasing filament which give rise to localised reflections with minimal rises in threshold current. Control of both position and depth enables one to sculpture the modal envelope so as to form singlemode Fabry-Perot lasers with 30 dB of mode suppression, temperature stable over 30/spl deg/C with an increase in threshold of a few milliamps. Modelling results show an effective reflectivity can be allocated to the etched pit and this is an order of magnitude below the cleaved facet reflectivity.
{"title":"Longitudinal mode control in Fabry-Perot lasers","authors":"D. Kozlowski, J. Young, J. England, R. Plumb","doi":"10.1109/EDMO.1995.493700","DOIUrl":"https://doi.org/10.1109/EDMO.1995.493700","url":null,"abstract":"Localised reflections within the lasing filament of Fabry-Perot lasers cause spectral perturbations. Focused Ga/sup +/ ion beam etching can be used to form steep walled pits of submicron size in the lasing filament which give rise to localised reflections with minimal rises in threshold current. Control of both position and depth enables one to sculpture the modal envelope so as to form singlemode Fabry-Perot lasers with 30 dB of mode suppression, temperature stable over 30/spl deg/C with an increase in threshold of a few milliamps. Modelling results show an effective reflectivity can be allocated to the etched pit and this is an order of magnitude below the cleaved facet reflectivity.","PeriodicalId":431745,"journal":{"name":"Proceedings of the 3rd IEEE International Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications, EDMO 95","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131695295","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 : 1995-11-27DOI: 10.1109/EDMO.1995.493690
N. Lukyanchikova
The properties of the excess noise observed in a wide variety of optoelectronic devices based on homo- and heterojunctions in III-V and II-VI compounds are considered. It is shown that rather universal mechanism is responsible for this noise and its model is described. A number of technical applications of the results of measurements of this noise is presented and discussed.
{"title":"General results of investigation of the excess noise in optoelectronic devices and their application for improving the device performance","authors":"N. Lukyanchikova","doi":"10.1109/EDMO.1995.493690","DOIUrl":"https://doi.org/10.1109/EDMO.1995.493690","url":null,"abstract":"The properties of the excess noise observed in a wide variety of optoelectronic devices based on homo- and heterojunctions in III-V and II-VI compounds are considered. It is shown that rather universal mechanism is responsible for this noise and its model is described. A number of technical applications of the results of measurements of this noise is presented and discussed.","PeriodicalId":431745,"journal":{"name":"Proceedings of the 3rd IEEE International Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications, EDMO 95","volume":"194 12","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120940448","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 : 1995-11-27DOI: 10.1109/EDMO.1995.493686
M. Bourke, K. Hilton, M. Crouch, M. Kane, N. Borsing, T. Russell
Reactive ion etching is becoming increasingly widespread in the fabrication of III-V semiconductor devices. Particular applications include optical waveguides, heterojunction bipolar transistors (HBTs) and FET/HEMT type devices. Etch depth control is a critical issue in the fabrication of many devices. Optical waveguides require accurate etch depths for optical mode control whereas in the fabrication of HBTs there is a requirement to access a thin base layer. It is possible to fabricate devices using a "dead reckoning" method-however, this has proved not to be very accurate and a form of end point detection is required. A number of end point detection techniques are available and include optical emission spectroscopy, optical reflectometry and mass spectroscopy. This paper will compare all three methods and demonstrate weaknesses and strong points for each. Particular attention will be given to optical reflectometry and mass spectroscopy in the fabrication of HBTs.
{"title":"The application of end point detection in the fabrication of optical and microwave devices","authors":"M. Bourke, K. Hilton, M. Crouch, M. Kane, N. Borsing, T. Russell","doi":"10.1109/EDMO.1995.493686","DOIUrl":"https://doi.org/10.1109/EDMO.1995.493686","url":null,"abstract":"Reactive ion etching is becoming increasingly widespread in the fabrication of III-V semiconductor devices. Particular applications include optical waveguides, heterojunction bipolar transistors (HBTs) and FET/HEMT type devices. Etch depth control is a critical issue in the fabrication of many devices. Optical waveguides require accurate etch depths for optical mode control whereas in the fabrication of HBTs there is a requirement to access a thin base layer. It is possible to fabricate devices using a \"dead reckoning\" method-however, this has proved not to be very accurate and a form of end point detection is required. A number of end point detection techniques are available and include optical emission spectroscopy, optical reflectometry and mass spectroscopy. This paper will compare all three methods and demonstrate weaknesses and strong points for each. Particular attention will be given to optical reflectometry and mass spectroscopy in the fabrication of HBTs.","PeriodicalId":431745,"journal":{"name":"Proceedings of the 3rd IEEE International Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications, EDMO 95","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128491079","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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