Volume 14 Issue 5
Sep.  2021
Turn off MathJax
Article Contents
HU Si-qi, TIAN Rui-juan, GAN Xue-tao. Two-dimensional material photodetector for hybrid silicon photonics[J]. Chinese Optics, 2021, 14(5): 1039-1055. doi: 10.37188/CO.2021-0003
Citation: HU Si-qi, TIAN Rui-juan, GAN Xue-tao. Two-dimensional material photodetector for hybrid silicon photonics[J]. Chinese Optics, 2021, 14(5): 1039-1055. doi: 10.37188/CO.2021-0003

Two-dimensional material photodetector for hybrid silicon photonics

doi: 10.37188/CO.2021-0003
Funds:  Supported by National Key R&D Program of China (No. 2018YFA0307200); National Natural Science Foundation of China (No. 61775183); Fundamental Research Funds for the Central Universities (No. 3102017jc01001)
More Information
  • Corresponding author: xuetaogan@nwpu.edu.cn
  • Received Date: 08 Jan 2021
  • Rev Recd Date: 02 Feb 2021
  • Available Online: 27 Mar 2021
  • Publish Date: 18 Sep 2021
  • Two-dimensional (2D) materials provide new development opportunities for silicon-based integrated optoelectronic devices due to their unique structure and excellent electronic and optoelectronic properties. In recent years, 2D material-based photodetectors for hybrid-integrated silicon photonics have been widely studied. Based on the basic characteristics of several 2D materials and the photodetection mechanisms, this paper reviews the research progress of silicon photonic integrated photodetectors based on 2D materials and summarizes existing device structure and performance. Finally, prospects for strategies to obtain high-performance silicon photonic integrated 2D material photodetectors and their commercial applicability are presented with considerations for large-scale 2D material integrations, device structure, and metal-semiconductor interface optimizations, as well as emerging 2D materials.


  • loading
  • [1]
    URINO Y, NAKAMURA T, ARAKAWA Y. Silicon optical interposers for high-density optical interconnects[M]. PAVESI L, LOCKWOOD D J. Silicon Photonics III: Systems and Applications. Berlin, Heidelberg: Springer, 2016: 1-39.
    BERGMAN K, SHALF J, HAUSKEN T. Optical interconnects and extreme computing[J]. Optics and Photonics News, 2016, 27(4): 32-39. doi: 10.1364/OPN.27.4.000032
    HO R, MAI K W, HOROWITZ M A. The future of wires[J]. Proceedings of the IEEE, 2001, 89(4): 490-504. doi: 10.1109/5.920580
    FEY D. Architectures and technologies for an optoelectronic VLSI[J]. Optik, 2001, 112(7): 274-282. doi: 10.1078/0030-4026-00057
    郝然. 对硅基光电子技术发展的思考[J]. 中兴通讯技术,2017,23(5):52-55.

    HAO R. Development of the silicon photonic technology[J]. ZTE Technology Journal, 2017, 23(5): 52-55. (in Chinese)
    LEE K K, LIM D R, LUAN H C, et al. Effect of Size and Roughness on Light Transmission in a Si/SiO2 waveguide: experiments and model[J]. Applied Physics Letters, 2000, 77(11): 1617-1619. doi: 10.1063/1.1308532
    LEE B G, CHEN X G, BIBERMAN A, et al. Ultrahigh-bandwidth silicon photonic nanowire waveguides for on-chip networks[J]. IEEE Photonics Technology Letters, 2008, 20(6): 398-400. doi: 10.1109/LPT.2008.916912
    OSGOOD JR R M, PANOIU N C, DADAP J I, et al. Engineering nonlinearities in nanoscale optical systems: physics and applications in dispersion-engineered silicon nanophotonic wires[J]. Advances in Optics and Photonics, 2009, 1(1): 162-235. doi: 10.1364/AOP.1.000162
    ORCUTT J S, KHILO A, HOLZWARTH C W, et al. Nanophotonic Integration in State-of-the-Art CMOS Foundries[J]. Optics Express, 2011, 19(3): 2335-2346. doi: 10.1364/OE.19.002335
    YOU J, LAVDAS S, PANOIU N C. Theoretical comparative analysis of BER in multi-channel systems with strip and photonic crystal silicon waveguides[J]. IEEE Journal of Selected Topics in Quantum Electronics, 2016, 22(2): 4400810.
    YOUNGBLOOD N, LI M. Integration of 2D materials on a silicon photonics platform for optoelectronics applications[J]. Nanophotonics, 2016, 6(6): 1205-1218. doi: 10.1515/nanoph-2016-0155
    BOLKHOVITYANOV Y B, PCHELYAKOV O P. GaAs epitaxy on Si substrates: modern status of research and engineering[J]. Physics-Uspekhi, 2008, 51(5): 437-456. doi: 10.1070/PU2008v051n05ABEH006529
    MICHEL J, LIU J F, KIMERLING L C. High-performance Ge-on-Si photodetectors[J]. Nature Photonics, 2010, 4(8): 527-534. doi: 10.1038/nphoton.2010.157
    AKINWANDE D, HUYGHEBAERT C, WANG C H, et al. Graphene and two-dimensional materials for silicon technology[J]. Nature, 2019, 573(7775): 507-518. doi: 10.1038/s41586-019-1573-9
    LIU M, YIN X B, ULIN-AVILA E, et al. A graphene-based broadband optical modulator[J]. Nature, 2011, 474(7349): 64-67. doi: 10.1038/nature10067
    GAO A Y, LAI J W, WANG Y J, et al. Observation of ballistic avalanche phenomena in nanoscale vertical InSe/BP heterostructures[J]. Nature Nanotechnology, 2019, 14(3): 217-222. doi: 10.1038/s41565-018-0348-z
    LONG M SH, WANG P, FANG H H, et al. Progress, challenges, and opportunities for 2D material based photodetectors[J]. Advanced Functional Materials, 2019, 29(19): 1803807. doi: 10.1002/adfm.201803807
    肖建花, 蒋亚东, 王洋, 等. 二极管型近红外聚合物光电探测器研究进展[J]. 红外技术,2020,42(10):917-926. doi: 10.3724/SP.J.7103116028

    XIAO J H, JIANG Y D, WANG Y, et al. Review of near-infrared polymer photodiodes[J]. Infrared Technology, 2020, 42(10): 917-926. (in Chinese) doi: 10.3724/SP.J.7103116028
    朱晓秀, 葛咏, 李建军, 等. 量子点增强硅基探测成像器件的研究进展[J]. 中国光学,2020,13(1):62-74. doi: 10.3788/co.20201301.0062

    ZHU X X, GE Y, LI J J, et al. Research progress of quantum dot enhanced silicon-based photodetectors[J]. Chinese Optics, 2020, 13(1): 62-74. (in Chinese) doi: 10.3788/co.20201301.0062
    FIORI G, BONACCORSO F, IANNACCONE G, et al. Electronics based on two-dimensional materials[J]. Nature Nanotechnology, 2014, 9(10): 768-779. doi: 10.1038/nnano.2014.207
    ALLEN M J, TUNG V C, KANER R B. Honeycomb carbon: a review of graphene[J]. Chemical Reviews, 2010, 110(1): 132-145. doi: 10.1021/cr900070d
    MERIC I, HAN M Y, YOUNG A F, et al. Current saturation in zero-bandgap, top-gated graphene field-effect transistors[J]. Nature Nanotechnology, 2008, 3(11): 654-659. doi: 10.1038/nnano.2008.268
    REN L, ZHANG Q, YAO J, et al. Terahertz and infrared spectroscopy of gated large-area graphene[J]. Nano Letters, 2012, 12(7): 3711-3715. doi: 10.1021/nl301496r
    BOLOTIN K I, SIKES K J, JIANG Z, et al. Ultrahigh electron mobility in suspended graphene[J]. Solid State Communications, 2008, 146(9-10): 351-355. doi: 10.1016/j.ssc.2008.02.024
    BALANDIN A A, GHOSH S, BAO W ZH, et al. Superior thermal conductivity of single-layer graphene[J]. Nano Letters, 2008, 8(3): 902-907. doi: 10.1021/nl0731872
    JIANG T, YIN K, WANG C, et al. Ultrafast fiber lasers mode-locked by two-dimensional materials: review and prospect[J]. Photonics Research, 2020, 8(1): 78-90. doi: 10.1364/PRJ.8.000078
    DENG X H, LIU J T, YUAN J R, et al. Tunable THz absorption in graphene-based heterostructures[J]. Optics Express, 2014, 22(24): 30177-30183. doi: 10.1364/OE.22.030177
    FALKOVSKY L A. Optical properties of graphene[J]. Journal of Physics:Conference Series, 2008, 129: 012004. doi: 10.1088/1742-6596/129/1/012004
    ROMAGNOLI M, SORIANELLO V, MIDRIO M, et al. Graphene-based integrated photonics for next-generation datacom and telecom[J]. Nature Reviews Materials, 2018, 3(10): 392-414. doi: 10.1038/s41578-018-0040-9
    LI L K, YU Y J, YE G J, et al. Black phosphorus field-effect transistors[J]. Nature Nanotechnology, 2014, 9(5): 372-377. doi: 10.1038/nnano.2014.35
    LIU X L, RYDER C R, WELLS S A, et al. Resolving the in-plane anisotropic properties of black phosphorus[J]. Small Methods, 2017, 1(6): 1700143. doi: 10.1002/smtd.201700143
    WANG X M, LAN SH F. Optical properties of black phosphorus[J]. Advances in Optics and Photonics, 2016, 8(4): 618-655. doi: 10.1364/AOP.8.000618
    DAS S, ZHANG W, DEMARTEAU M, et al. Tunable transport gap in phosphorene[J]. Nano Letters, 2014, 14(10): 5733-5739. doi: 10.1021/nl5025535
    ZHENG J L, YANG ZH H, SI C, et al. Black phosphorus based all-optical-signal-processing: toward high performances and enhanced stability[J]. ACS Photonics, 2017, 4(6): 1466-1476. doi: 10.1021/acsphotonics.7b00231
    RYDER C R, WOOD J D, WELLS S A, et al. Chemically tailoring semiconducting two-dimensional transition metal dichalcogenides and black phosphorus[J]. ACS Nano, 2016, 10(4): 3900-3917. doi: 10.1021/acsnano.6b01091
    DENG B CH, TRAN V, XIE Y J, et al. Efficient electrical control of thin-film black phosphorus bandgap[J]. Nature Communications, 2017, 8(1): 14474. doi: 10.1038/ncomms14474
    YI Y, SUN ZH B, LI J, et al. Optical and optoelectronic properties of black phosphorus and recent photonic and optoelectronic applications[J]. Small Methods, 2019, 3(10): 1900165. doi: 10.1002/smtd.201900165
    WANG K P, SZYDŁOWSKA B M, WANG G ZH, et al. Ultrafast nonlinear excitation dynamics of black phosphorus nanosheets from visible to mid-infrared[J]. ACS Nano, 2016, 10(7): 6923-6932. doi: 10.1021/acsnano.6b02770
    DENG B CH, FRISENDA R, LI CH, et al. Progress on black phosphorus photonics[J]. Advanced Optical Materials, 2018, 6(19): 1800365. doi: 10.1002/adom.201800365
    CASTELLANOS-GOMEZ A, VICARELLI L, PRADA E, et al. Isolation and characterization of few-layer black phosphorus[J]. 2D Materials, 2014, 1(2): 025001. doi: 10.1088/2053-1583/1/2/025001
    CHHOWALLA M, SHIN H S, EDA G, et al. The chemistry of two-dimensional layered transition metal dichalcogenide nanosheets[J]. Nature Chemistry, 2013, 5(4): 263-275. doi: 10.1038/nchem.1589
    CHERNIKOV A, BERKELBACH T C, HILL H M, et al. Exciton binding energy and nonhydrogenic rydberg series in monolayer WS2[J]. Physical Review Letters, 2014, 113(7): 076802. doi: 10.1103/PhysRevLett.113.076802
    SCHNEIDER C, GLAZOV M M, KORN T, et al. Two-dimensional semiconductors in the regime of strong light-matter coupling[J]. Nature Communications, 2018, 9(1): 2695. doi: 10.1038/s41467-018-04866-6
    RAHMAN I A, PURQON A. First principles study of molybdenum disulfide electronic structure[J]. Journal of Physics:Conference Series, 2017, 877(1): 012026.
    CONG CH X, SHANG J Z, WANG Y L, et al. Optical properties of 2D semiconductor WS2[J]. Advanced Optical Materials, 2018, 6(1): 1700767. doi: 10.1002/adom.201700767
    DELPHINE S M, JAYACHANDRAN M, SANJEEVIRAJA C. Review of material properties of (Mo/W)Se2-layered compound semiconductors useful for photoelectrochemical solar cells[J]. Crystallography Reviews, 2011, 17(4): 281-301. doi: 10.1080/0889311X.2011.611130
    MITIOGLU A A, PLOCHOCKA P, GRANADOS DEL AGUILA Á, et al. Optical investigation of monolayer and bulk tungsten diselenide (WSe2) in high magnetic fields[J]. Nano Letters, 2015, 15(7): 4387-4392. doi: 10.1021/acs.nanolett.5b00626
    MAK K F, LEE C, HONE J, et al. Atomically thin MoS2: a new direct-gap semiconductor[J]. Physical Review Letters, 2010, 105(13): 136805. doi: 10.1103/PhysRevLett.105.136805
    TAN CH L, ZHANG H. Two-dimensional transition metal dichalcogenide nanosheet-based composites[J]. Chemical Society Reviews, 2015, 44(9): 2713-2731. doi: 10.1039/C4CS00182F
    YE Z L, CAO T, O’BRIEN K, et al. Probing excitonic dark states in single-layer tungsten disulphide[J]. Nature, 2014, 513(7517): 214-218. doi: 10.1038/nature13734
    DEAN C R, YOUNG A F, MERIC I, et al. Boron nitride substrates for high-quality graphene electronics[J]. Nature Nanotechnology, 2010, 5(10): 722-726. doi: 10.1038/nnano.2010.172
    VUONG T Q P, CASSABOIS G, VALVIN P, et al. Deep ultraviolet emission in hexagonal boron nitride grown by high-temperature molecular beam epitaxy[J]. 2D Materials, 2017, 4(2): 021023. doi: 10.1088/2053-1583/aa604a
    CAI Q R, SCULLION D, GAN W, et al. High thermal conductivity of high-quality monolayer boron nitride and its thermal expansion[J]. Science Advances, 2019, 5(6): eaav0129. doi: 10.1126/sciadv.aav0129
    VELICKÝ M, TOTH P S. From two-dimensional materials to their heterostructures: an electrochemist’s perspective[J]. Applied Materials Today, 2017, 8: 68-103. doi: 10.1016/j.apmt.2017.05.003
    GEIM A K, GRIGORIEVA I V. Van der waals heterostructures[J]. Nature, 2013, 499(7459): 419-425. doi: 10.1038/nature12385
    LIU Y D, FANG H L, RASMITA A, et al. Room temperature nanocavity laser with interlayer excitons in 2D heterostructures[J]. Science Advances, 2019, 5(4): eaav4506. doi: 10.1126/sciadv.aav4506
    LIU Y P, ZHANG S Y, HE J, et al. Recent progress in the fabrication, properties, and devices of heterostructures based on 2D materials[J]. Nano-Micro Letters, 2019, 11(1): 13. doi: 10.1007/s40820-019-0245-5
    JIANG X T, KUKLIN A V, BAEV A, et al. Two-dimensional MXenes: from morphological to optical, electric, and magnetic properties and applications[J]. Physics Reports, 2020, 848: 1-58. doi: 10.1016/j.physrep.2019.12.006
    BROTONS-GISBERT M, ANDRES-PENARES D, SUH J, et al. Nanotexturing to enhance photoluminescent response of atomically thin indium selenide with highly tunable band gap[J]. Nano Letters, 2016, 16(5): 3221-3229. doi: 10.1021/acs.nanolett.6b00689
    BANDURIN D A, TYURNINA A V, YU G L, et al. High electron mobility, quantum hall effect and anomalous optical response in atomically thin InSe[J]. Nature Nanotechnology, 2017, 12(3): 223-227. doi: 10.1038/nnano.2016.242
    LI ZH J, QIAO H, GUO ZH N, et al. High-performance photo-electrochemical photodetector based on liquid-exfoliated few-layered inse nanosheets with enhanced stability[J]. Advanced Functional Materials, 2018, 28(16): 1705237. doi: 10.1002/adfm.201705237
    JIANG X T, ZHAO X M, BAO W L, et al. Graphdiyne nanosheets for multicolor random lasers[J]. ACS Applied Nano Materials, 2020, 3(6): 4990-4996. doi: 10.1021/acsanm.0c00859
    LI P F, CHEN Y, YANG T SH, et al. Two-dimensional CH3NH3PbI3 perovskite nanosheets for ultrafast pulsed fiber lasers[J]. ACS Applied Materials &Interfaces, 2017, 9(14): 12759-12765.
    DE QUILETTES D W, VORPAHL S M, STRANKS S D, et al. Impact of microstructure on local carrier lifetime in perovskite solar cells[J]. Science, 2015, 348(6235): 683-686. doi: 10.1126/science.aaa5333
    TIAN Y X, PETER M, UNGER E, et al. Mechanistic insights into perovskite photoluminescence enhancement: light curing with oxygen can boost yield thousandfold[J]. Physical Chemistry Chemical Physics, 2015, 17(38): 24978-24987. doi: 10.1039/C5CP04410C
    KONSTANTATOS G, SARGENT E H. Nanostructured materials for photon detection[J]. Nature Nanotechnology, 2010, 5(6): 391-400. doi: 10.1038/nnano.2010.78
    KONSTANTATOS G, BADIOLI M, GAUDREAU L, et al. Hybrid graphene-quantum dot phototransistors with ultrahigh gain[J]. Nature Nanotechnology, 2012, 7(6): 363-368. doi: 10.1038/nnano.2012.60
    FANG H H, HU W D. Photogating in low dimensional photodetectors[J]. Advanced Science, 2017, 4(12): 1700323. doi: 10.1002/advs.201700323
    SZE S M, NG K K. Physics of Semiconductor Devices[M]. 3rd ed. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2006.
    XU X D, GABOR N M, ALDEN J S, et al. Photo-thermoelectric effect at a graphene interface junction[J]. Nano Letters, 2010, 10(2): 562-566. doi: 10.1021/nl903451y
    YUAN H, LIU X, AFSHINMANESH F, et al. Polarization-sensitive broadband photodetector using a black phosphorus vertical p-n junction[J]. Nature Nanotechnology, 2015, 10(8): 707-713.
    BOYD R W, HILBORN R C. Radiometry and the detection of optical radiation[J]. American Journal of Physics, 1984, 52(7): 668-669. doi: 10.1119/1.13578
    FREITAG M, LOW T, XIA F N, et al. Photoconductivity of biased graphene[J]. Nature Photonics, 2013, 7(1): 53-59. doi: 10.1038/nphoton.2012.314
    LOW T, RODIN A S, CARVALHO A, et al. Tunable optical properties of multilayer black phosphorus thin films[J]. Physical Review B, 2014, 90(7): 075434. doi: 10.1103/PhysRevB.90.075434
    XIA F N, MUELLER T, LIN Y M, et al. Ultrafast graphene photodetector[J]. Nature Nanotechnology, 2009, 4(12): 839-843. doi: 10.1038/nnano.2009.292
    GAN X T, SHIUE R J, GAO Y D, et al. Chip-integrated ultrafast graphene photodetector with high responsivity[J]. Nature Photonics, 2013, 7(11): 883-887. doi: 10.1038/nphoton.2013.253
    WANG X M, CHENG ZH ZH, XU K, et al. High-responsivity graphene/silicon-heterostructure waveguide photodetectors[J]. Nature Photonics, 2013, 7(11): 888-891. doi: 10.1038/nphoton.2013.241
    POSPISCHIL A, HUMER M, FURCHI M M, et al. CMOS-compatible graphene photodetector covering all optical communication bands[J]. Nature Photonics, 2013, 7(11): 892-896. doi: 10.1038/nphoton.2013.240
    SHIUE R J, GAO Y D, WANG Y F, et al. High-responsivity graphene-boron nitride photodetector and autocorrelator in a silicon photonic integrated circuit[J]. Nano Letters, 2015, 15(11): 7288-7293. doi: 10.1021/acs.nanolett.5b02368
    SCHULER S, SCHALL D, NEUMAIER D, et al. Controlled generation of a p–n junction in a waveguide integrated graphene photodetector[J]. Nano Letters, 2016, 16(11): 7107-7112. doi: 10.1021/acs.nanolett.6b03374
    SCHULER S, SCHALL D, NEUMAIER D, et al. Graphene photodetector integrated on a photonic crystal defect waveguide[J]. ACS Photonics, 2018, 5(12): 4758-4763. doi: 10.1021/acsphotonics.8b01128
    LIU J F, MICHEL J, GIZIEWICZ W, et al. High-performance, tensile-strained Ge p-i-n photodetectors on a Si platform[J]. Applied Physics Letters, 2005, 87(10): 103501. doi: 10.1063/1.2037200
    MA P, SALAMIN Y, BAEUERLE B, et al. Plasmonically enhanced graphene photodetector featuring 100 Gbit/s data reception, high responsivity, and compact size[J]. ACS Photonics, 2019, 6(1): 154-161. doi: 10.1021/acsphotonics.8b01234
    GUO J SH, LI J, LIU CH Y, et al. High-performance silicon-graphene hybrid plasmonic waveguide photodetectors beyond 1.55 μm[J]. Light:Science &Applications, 2020, 9(1): 29.
    BUSCEMA M, GROENENDIJK D J, BLANTER S I, et al. Fast and broadband photoresponse of few-layer black phosphorus field-effect transistors[J]. Nano Letters, 2014, 14(6): 3347-3352. doi: 10.1021/nl5008085
    YOUNGBLOOD N, CHEN CH, KOESTER S J, et al. Waveguide-integrated black phosphorus photodetector with high responsivity and low dark current[J]. Nature Photonics, 2015, 9(4)-252.
    CHEN CH, YOUNGBLOOD N, PENG R M, et al. Three-dimensional integration of black phosphorus photodetector with silicon photonics and nanoplasmonics[J]. Nano Letters, 2017, 17(2): 985-991. doi: 10.1021/acs.nanolett.6b04332
    YIN Y L, CAO R, GUO J SH, et al. High-speed and high-responsivity hybrid silicon/black-phosphorus waveguide photodetectors at 2 μm[J]. Laser &Photonics Reviews, 2019, 13(6): 1900032.
    HUANG L, DONG B W, GUO X, et al. Waveguide-integrated black phosphorus photodetector for mid-infrared applications[J]. ACS Nano, 2019, 13(1): 913-921. doi: 10.1021/acsnano.8b08758
    THAKAR K, LODHA S. Optoelectronic and photonic devices based on transition metal dichalcogenides[J]. Materials Research Express, 2020, 7(1): 014002. doi: 10.1088/2053-1591/ab5c9c
    YANG J, LÜ T Y, MYINT Y W, et al. Robust excitons and trions in monolayer MoTe2[J]. ACS Nano, 2015, 9(6): 6603-6609. doi: 10.1021/acsnano.5b02665
    BIE Y Q, GROSSO G, HEUCK M, et al. A MoTe2-based light-emitting diode and photodetector for silicon photonic integrated circuits[J]. Nature Nanotechnology, 2017, 12(12): 1124-1129. doi: 10.1038/nnano.2017.209
    MA P, FLÖRY N, SALAMIN Y, et al. Fast MoTe2 waveguide photodetector with high sensitivity at telecommunication wavelengths[J]. ACS Photonics, 2018, 5(5): 1846-1852. doi: 10.1021/acsphotonics.8b00068
    FLÖRY N, MA P, SALAMIN Y, et al. Waveguide-Integrated van der waals heterostructure photodetector at telecom wavelengths with high speed and high responsivity[J]. Nature Nanotechnology, 2020, 15(2): 118-124. doi: 10.1038/s41565-019-0602-z
    MAITI R, PATIL C, SAADI M A S R, et al. Strain-engineered high-responsivity MoTe2 photodetector for silicon photonic integrated circuits[J]. Nature Photonics, 2020, 14(9): 578-584. doi: 10.1038/s41566-020-0647-4
    GAO Y, ZHOU G D, TSANG H K, et al. High-speed van der waals heterostructure tunneling photodiodes integrated on silicon nitride waveguides[J]. Optica, 2019, 6(4): 514-517. doi: 10.1364/OPTICA.6.000514
  • 加载中


    通讯作者: 陈斌, bchen63@163.com
    • 1. 

      沈阳化工大学材料科学与工程学院 沈阳 110142

    1. 本站搜索
    2. 百度学术搜索
    3. 万方数据库搜索
    4. CNKI搜索


    Article views(2705) PDF downloads(573) Cited by()
    Proportional views


    DownLoad:  Full-Size Img  PowerPoint