Pub Date : 1990-04-23DOI: 10.1109/ICIPRM.1990.203037
C. Zeisse, R. Nguyen, T. Vu, L. Messick, K. L. Moazed
A junction field effect transistor (JFET) that meets the numerical requirements of an electrooptic receiver sensitive to 1.3 and 1.55 mu m optical radiation is reported. It was made by diffusing zinc into an epitaxial channel of indium phosphide. Low-frequency characterization showed that it has a transconductance of 240 mS/mm, a capacitance of 3.25 pF/mm, a gate-to-source leakage current of 10 nA at a bias of -4 V, and a one week stability of 3 mA out of 145 mA under the application of constant bias. The calculated unity current gain frequency is 12 GHz. The device should be suitable for wideband DC coupled integrated circuits made with InP-based materials.<>
{"title":"An indium phosphide diffused junction field effect transistor","authors":"C. Zeisse, R. Nguyen, T. Vu, L. Messick, K. L. Moazed","doi":"10.1109/ICIPRM.1990.203037","DOIUrl":"https://doi.org/10.1109/ICIPRM.1990.203037","url":null,"abstract":"A junction field effect transistor (JFET) that meets the numerical requirements of an electrooptic receiver sensitive to 1.3 and 1.55 mu m optical radiation is reported. It was made by diffusing zinc into an epitaxial channel of indium phosphide. Low-frequency characterization showed that it has a transconductance of 240 mS/mm, a capacitance of 3.25 pF/mm, a gate-to-source leakage current of 10 nA at a bias of -4 V, and a one week stability of 3 mA out of 145 mA under the application of constant bias. The calculated unity current gain frequency is 12 GHz. The device should be suitable for wideband DC coupled integrated circuits made with InP-based materials.<<ETX>>","PeriodicalId":138960,"journal":{"name":"International Conference on Indium Phosphide and Related Materials","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131256055","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 : 1990-04-23DOI: 10.1109/ICIPRM.1990.203052
S. Pearton
The use of ion implantation to create doped regions or high-resistivity layers in InP, InGaAs and AlInAs is reviewed. Recent results on carbon implantation into these materials show that it behaves predominantly as a donor in InP but can give rise to p-type doping levels above 10/sup 19/ cm/sup -3/ in InGaAs and AlInAs. The diffusivity of carbon in all of these materials is measured at 800 degrees C. The use of a SiC-coated graphite susceptor provides degradation-free rapid thermal annealing of the In-based III-V semiconductors for high-temperature implant activation. Smooth, residue-free dry etching of these materials is obtained using CH/sub 4//H/sub 2/ mixtures. The use of microwave (2.45 GHz) electron cyclotron resonance (ECR) discharges minimizes the depth of lattice disorder resulting from dry etching, relative to conventional RF discharges. The characteristics of ion milling of InP are reviewed. It is seen that postmilling annealing cannot restore the rear-surface crystallinity after 500 eV Ar/sup +/ ion bombardment of InP, and wet chemical removal of approximately 650 A is necessary.<>
{"title":"Ion beam processing and rapid thermal annealing of InP and related compounds","authors":"S. Pearton","doi":"10.1109/ICIPRM.1990.203052","DOIUrl":"https://doi.org/10.1109/ICIPRM.1990.203052","url":null,"abstract":"The use of ion implantation to create doped regions or high-resistivity layers in InP, InGaAs and AlInAs is reviewed. Recent results on carbon implantation into these materials show that it behaves predominantly as a donor in InP but can give rise to p-type doping levels above 10/sup 19/ cm/sup -3/ in InGaAs and AlInAs. The diffusivity of carbon in all of these materials is measured at 800 degrees C. The use of a SiC-coated graphite susceptor provides degradation-free rapid thermal annealing of the In-based III-V semiconductors for high-temperature implant activation. Smooth, residue-free dry etching of these materials is obtained using CH/sub 4//H/sub 2/ mixtures. The use of microwave (2.45 GHz) electron cyclotron resonance (ECR) discharges minimizes the depth of lattice disorder resulting from dry etching, relative to conventional RF discharges. The characteristics of ion milling of InP are reviewed. It is seen that postmilling annealing cannot restore the rear-surface crystallinity after 500 eV Ar/sup +/ ion bombardment of InP, and wet chemical removal of approximately 650 A is necessary.<<ETX>>","PeriodicalId":138960,"journal":{"name":"International Conference on Indium Phosphide and Related Materials","volume":"215 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132770470","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 : 1990-04-23DOI: 10.1109/ICIPRM.1990.202989
S. Bailey, N. Fatemi, G. Landis, D. Brinker, M. Faur
InP solar cells with a V-grooved front surface were fabricated and tested. The cells were made by the closed-ampoule thermal diffusion of sulfur into Zn-doped InP substrates on which the grooves were formed by a wet-chemical anisotropic etch. Reflectivity measurements show significantly lower reflectance for the microgrooved cell compared to a planar wafer. Cell short-circuit current, open-circuit voltage, efficiency, and quantum efficiency as a function of wavelength were measured. Compared to planar cells, the V-grooved cells showed increased short circuit current over the entire spectral range, with a slight decrease in voltage.<>
{"title":"Application of V-groove technology to InP solar cells","authors":"S. Bailey, N. Fatemi, G. Landis, D. Brinker, M. Faur","doi":"10.1109/ICIPRM.1990.202989","DOIUrl":"https://doi.org/10.1109/ICIPRM.1990.202989","url":null,"abstract":"InP solar cells with a V-grooved front surface were fabricated and tested. The cells were made by the closed-ampoule thermal diffusion of sulfur into Zn-doped InP substrates on which the grooves were formed by a wet-chemical anisotropic etch. Reflectivity measurements show significantly lower reflectance for the microgrooved cell compared to a planar wafer. Cell short-circuit current, open-circuit voltage, efficiency, and quantum efficiency as a function of wavelength were measured. Compared to planar cells, the V-grooved cells showed increased short circuit current over the entire spectral range, with a slight decrease in voltage.<<ETX>>","PeriodicalId":138960,"journal":{"name":"International Conference on Indium Phosphide and Related Materials","volume":"139 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133126416","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 : 1990-04-23DOI: 10.1109/ICIPRM.1990.202984
P.M. Smith, P. Chao, P. Ho, K. Duh, M. Kao, J. Ballingall, S. Allen, A. Tessmer
The development of HEMTs based on the InAlAs/InGaAs/InP materials system for high-frequency analog applications is reported. Devices with 0.15- mu m gatelengths have demonstrated extrinsic transconductance of 1500 mS/mm and extrapolated maximum frequency of oscillation f/sub max/ greater than 450 GHz. The noise figure is the lowest of any room-temperature receiver technology over the 5 to 100 GHz frequency range. Prospects for power amplification are excellent: power-added efficiency of 41% has already been demonstrated at 60 GHz. The integration of these devices into monolithic microwave integrated circuits (MMICs) is discussed.<>
{"title":"Microwave InAlAs/InGaAs/InP HEMTs: status and applications","authors":"P.M. Smith, P. Chao, P. Ho, K. Duh, M. Kao, J. Ballingall, S. Allen, A. Tessmer","doi":"10.1109/ICIPRM.1990.202984","DOIUrl":"https://doi.org/10.1109/ICIPRM.1990.202984","url":null,"abstract":"The development of HEMTs based on the InAlAs/InGaAs/InP materials system for high-frequency analog applications is reported. Devices with 0.15- mu m gatelengths have demonstrated extrinsic transconductance of 1500 mS/mm and extrapolated maximum frequency of oscillation f/sub max/ greater than 450 GHz. The noise figure is the lowest of any room-temperature receiver technology over the 5 to 100 GHz frequency range. Prospects for power amplification are excellent: power-added efficiency of 41% has already been demonstrated at 60 GHz. The integration of these devices into monolithic microwave integrated circuits (MMICs) is discussed.<<ETX>>","PeriodicalId":138960,"journal":{"name":"International Conference on Indium Phosphide and Related Materials","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131319554","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 : 1990-04-23DOI: 10.1109/ICIPRM.1990.203056
I. Adesida, E. Andideh, C. Jones, N. Finnegan
Analyses of InP and SiO/sub 2/ mask surfaces etched in CH/sub 4//H/sub 2/ plasma have been performed using X-ray photoelectron spectroscopy and Auger electron spectroscopy. A relatively thick polymer layer was detected on the mask surface, whereas polymer deposition on etched InP surface was insignificant even under plasma conditions designed to enhance polymer formation. Subsequent processing of etched InP in O/sub 2/ plasma followed by a dip in HCl/H/sub 2/O was found to be sufficient for obtaining clean surfaces with good stoichiometry.<>
{"title":"Etching of InP in methane-based plasmas","authors":"I. Adesida, E. Andideh, C. Jones, N. Finnegan","doi":"10.1109/ICIPRM.1990.203056","DOIUrl":"https://doi.org/10.1109/ICIPRM.1990.203056","url":null,"abstract":"Analyses of InP and SiO/sub 2/ mask surfaces etched in CH/sub 4//H/sub 2/ plasma have been performed using X-ray photoelectron spectroscopy and Auger electron spectroscopy. A relatively thick polymer layer was detected on the mask surface, whereas polymer deposition on etched InP surface was insignificant even under plasma conditions designed to enhance polymer formation. Subsequent processing of etched InP in O/sub 2/ plasma followed by a dip in HCl/H/sub 2/O was found to be sufficient for obtaining clean surfaces with good stoichiometry.<<ETX>>","PeriodicalId":138960,"journal":{"name":"International Conference on Indium Phosphide and Related Materials","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117052348","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 : 1990-04-23DOI: 10.1109/ICIPRM.1990.203066
B. Miller, M. Young, U. Koren, T. Koch, M. Oron, R. Gnall, J. Zucker, K. Jones, F. Hernández-Gil, J. L. deMiguel
It has been shown that bulk layers of InGaAs and InGaAsP grown using tertiarybutylarsine (TBA) have nearly as good electrical and optical properties as AsH/sub 3/-grown layers. As a consequence conventional InGaAsP lasers at 1.3 mu m were grown by TBA and were found to have properties as good as those of AsH/sub 3/ lasers. Investigations into other components of PIC circuits grown by using TBA as substitute for AsH/sub 3/ are presented. Studies of multi-quantum-well (MQW) and strained-layer MQW lasers, a four-port directional coupler optical switch, and quantum-confined Stark effect modulator structures grown by this technique are reported. The components are intended for use in photonic integrated circuits. In all cases satisfactory performance is demonstrated.<>
{"title":"Tertiarybutylarsine as a substitute for AsH3: application to InGaAs/InP photonic integrated circuits","authors":"B. Miller, M. Young, U. Koren, T. Koch, M. Oron, R. Gnall, J. Zucker, K. Jones, F. Hernández-Gil, J. L. deMiguel","doi":"10.1109/ICIPRM.1990.203066","DOIUrl":"https://doi.org/10.1109/ICIPRM.1990.203066","url":null,"abstract":"It has been shown that bulk layers of InGaAs and InGaAsP grown using tertiarybutylarsine (TBA) have nearly as good electrical and optical properties as AsH/sub 3/-grown layers. As a consequence conventional InGaAsP lasers at 1.3 mu m were grown by TBA and were found to have properties as good as those of AsH/sub 3/ lasers. Investigations into other components of PIC circuits grown by using TBA as substitute for AsH/sub 3/ are presented. Studies of multi-quantum-well (MQW) and strained-layer MQW lasers, a four-port directional coupler optical switch, and quantum-confined Stark effect modulator structures grown by this technique are reported. The components are intended for use in photonic integrated circuits. In all cases satisfactory performance is demonstrated.<<ETX>>","PeriodicalId":138960,"journal":{"name":"International Conference on Indium Phosphide and Related Materials","volume":"124 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116318708","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 : 1990-04-23DOI: 10.1109/ICIPRM.1990.202988
I. Weinberg, C. K. Swartz, D. Brinker, D. Wilt
The properties of InP solar cells, processed by OMCVD on silicon substrates with an intermediate GaAs layer (InP/GaAs/Si) and on GaAs substrates (InP/GaAs), were determined before and after irradiation with 10-MeV protons. The preirradiation transport properties were found to be influenced largely by dislocations occurring at the InP-GaAs interface. A carrier removal rate of 1.8*10/sup 3/ cm/sup -1/ was observed after irradiation to a proton fluence of 1.1*10/sup 13/ cm/sup -2/. Despite the high degree of defect generation, the radiation resistance, of the heteroepitaxial cells was considerably greater than that observed for monolithic n/sup +/p InP cells. The observed low cell efficiencies and high radiation resistance are attributed to the dominant effect of dislocations in the cell's p-base region.<>
{"title":"Heteroepitaxially grown InP solar cells","authors":"I. Weinberg, C. K. Swartz, D. Brinker, D. Wilt","doi":"10.1109/ICIPRM.1990.202988","DOIUrl":"https://doi.org/10.1109/ICIPRM.1990.202988","url":null,"abstract":"The properties of InP solar cells, processed by OMCVD on silicon substrates with an intermediate GaAs layer (InP/GaAs/Si) and on GaAs substrates (InP/GaAs), were determined before and after irradiation with 10-MeV protons. The preirradiation transport properties were found to be influenced largely by dislocations occurring at the InP-GaAs interface. A carrier removal rate of 1.8*10/sup 3/ cm/sup -1/ was observed after irradiation to a proton fluence of 1.1*10/sup 13/ cm/sup -2/. Despite the high degree of defect generation, the radiation resistance, of the heteroepitaxial cells was considerably greater than that observed for monolithic n/sup +/p InP cells. The observed low cell efficiencies and high radiation resistance are attributed to the dominant effect of dislocations in the cell's p-base region.<<ETX>>","PeriodicalId":138960,"journal":{"name":"International Conference on Indium Phosphide and Related Materials","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129734963","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 : 1990-04-23DOI: 10.1109/ICIPRM.1990.203065
S. Bahl, J. D. del Alamo
In/sub 0.52/Al/sub 0.48/As/n/sup +/-In/sub x/Ga/sub 1-x/As HFETs have been fabricated with InAs fractions between 0.53 and 0.7 in the channel. These HFETs, also called MIDFETs (metal-insulator doped-channel FETs), have a doped channel and an undoped wide-bandgap insulator. The enhancement of InAs in the channel results in a marked improvement in transconductance and peak drain current. Devices with L/sub g/=1 mu m and x=0.7 display an unprecedented I/sub d/ of 656 mA/mm and g/sub m/ of 296 mS/mm. As x is increased, however, there is an increase in the gate current, a dramatic decrease in the breakdown voltage, and a degradation of pinch-off. Leakage at the gate-mesa edge overlap is found to be partially responsible for these effects. To achieve the substantial gains in transport that higher InAs fractions offer, better isolation technology is required.<>
{"title":"An In/sub 0.52/Al/sub 0.48/As/n/sup +/-In/sub x/Ga/sub 1-x/As heterostructure field-effect transistor with an In-enriched channel","authors":"S. Bahl, J. D. del Alamo","doi":"10.1109/ICIPRM.1990.203065","DOIUrl":"https://doi.org/10.1109/ICIPRM.1990.203065","url":null,"abstract":"In/sub 0.52/Al/sub 0.48/As/n/sup +/-In/sub x/Ga/sub 1-x/As HFETs have been fabricated with InAs fractions between 0.53 and 0.7 in the channel. These HFETs, also called MIDFETs (metal-insulator doped-channel FETs), have a doped channel and an undoped wide-bandgap insulator. The enhancement of InAs in the channel results in a marked improvement in transconductance and peak drain current. Devices with L/sub g/=1 mu m and x=0.7 display an unprecedented I/sub d/ of 656 mA/mm and g/sub m/ of 296 mS/mm. As x is increased, however, there is an increase in the gate current, a dramatic decrease in the breakdown voltage, and a degradation of pinch-off. Leakage at the gate-mesa edge overlap is found to be partially responsible for these effects. To achieve the substantial gains in transport that higher InAs fractions offer, better isolation technology is required.<<ETX>>","PeriodicalId":138960,"journal":{"name":"International Conference on Indium Phosphide and Related Materials","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130659585","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 : 1990-04-23DOI: 10.1109/ICIPRM.1990.203007
A. Kasukawa, H. Okamoto
Long-wavelength GaInAs(P)/InP quantum well laser diodes (QW LDs) are described with respect to the epitaxial growth technique used, their QW structure, and the cavity design. QW LDs with graded-index separate-confinement heterostructure (GRIN-SCH), grown by metalorganic chemical vapor deposition (MOCVD), exhibit low threshold current density (410 A/cm/sup 2/), low threshold current (6 mA), high characteristic temperature (153 K), and high output power (100 mW). Preliminary aging tests have been carried out at 50 degrees C, 5 mW and at 70 degrees C, 5 mW. N appreciable change in driving current was seen after 7000 h, indicating the high reliability of these devices.<>
{"title":"Long wavelength quantum well laser diodes grown by metalorganic chemical vapor deposition","authors":"A. Kasukawa, H. Okamoto","doi":"10.1109/ICIPRM.1990.203007","DOIUrl":"https://doi.org/10.1109/ICIPRM.1990.203007","url":null,"abstract":"Long-wavelength GaInAs(P)/InP quantum well laser diodes (QW LDs) are described with respect to the epitaxial growth technique used, their QW structure, and the cavity design. QW LDs with graded-index separate-confinement heterostructure (GRIN-SCH), grown by metalorganic chemical vapor deposition (MOCVD), exhibit low threshold current density (410 A/cm/sup 2/), low threshold current (6 mA), high characteristic temperature (153 K), and high output power (100 mW). Preliminary aging tests have been carried out at 50 degrees C, 5 mW and at 70 degrees C, 5 mW. N appreciable change in driving current was seen after 7000 h, indicating the high reliability of these devices.<<ETX>>","PeriodicalId":138960,"journal":{"name":"International Conference on Indium Phosphide and Related Materials","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123194324","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 : 1990-04-23DOI: 10.1109/ICIPRM.1990.203049
Y. Wey, D. L. Crawford, J. Bowers, M. Hafich, G. Y. Robinson, F. Storz
The material and design constraints for high speed InGaAs/InP p-i-n photodetectors and the operation of such devices are discussed. The photodetector wafer was grown on
{"title":"Design of high speed GaInAs/InP p-i-n photodetectors","authors":"Y. Wey, D. L. Crawford, J. Bowers, M. Hafich, G. Y. Robinson, F. Storz","doi":"10.1109/ICIPRM.1990.203049","DOIUrl":"https://doi.org/10.1109/ICIPRM.1990.203049","url":null,"abstract":"The material and design constraints for high speed InGaAs/InP p-i-n photodetectors and the operation of such devices are discussed. The photodetector wafer was grown on","PeriodicalId":138960,"journal":{"name":"International Conference on Indium Phosphide and Related Materials","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131743381","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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