Chowdhury, Mazharul Huq (2010) Electrical Properties of Grain Boundaries in Low Doped Polycrystalline Materials with Applications to Detectors. Masters thesis, Concordia University.
Preview |
Text (application/pdf)
2MBChowdhury_MASc_S2011.pdf - Accepted Version |
Abstract
Polycrystalline materials are widely used in large area electronic devices such as flat panel x-ray image detectors, and solar cells due to their suitability to deposit over large area at low cost. The performance of polycrystalline-based flat panel detectors are showing encouraging results (good sensitivity, good resolution and acceptable dark current) and give possibility to replace existing x-ray film/screen cassette. Therefore large area polycrystalline based flat panel detectors have opened new clinical possibilities and the polycrystalline solar cells give the opportunity of manufacturing low cost photovoltaic cells. Consequently, active research has been carried out to find out suitable polycrystalline materials (e.g. HgI2, CdTe, CdZnTe, PbI2, PbO etc) for various large area applications. However a polycrystalline material is composed of micro crystallites joined together by grain boundaries (complex structure, consisting of a few atomic layers of disordered atoms) which posses trap centers for charge carriers. Therefore, grain boundaries can trap a large amount of charges during detector operation. A potential barrier for drifting carriers may exist at the grain boundary, which controls the carrier mobility. Moreover, the performance of these polycrystalline detectors are affected due to the polarization phenomena (any change in the performance of the detector after the detector biasing) under applied bias. Therefore, in this research work, an analytical model is developed to study the electrical properties (electric field and potential distributions, potential barrier height, and polarization phenomenon) of polycrystalline materials at different doping levels for detector and solar cell applications by considering an arbitrary amount of grain boundary charge and a finite width of grain boundary region. The general grain boundary model is also applicable to highly doped polycrystalline materials. The electric field and potential distributions are obtained by solving the Poisson’s equation in both depleted grains and grain boundary regions. The electric field and potential distributions across the detector are analyzed under various doping, trapping and applied biases. The electric field collapses, i.e., a nearly zero average electric field region exists in some part of the biased detector at high trapped charge densities at the grain boundaries. The model explains the conditions of existence of a zero average field region, i.e., it explains the polarization mechanisms in polycrystalline materials. The potential barrier at the grain boundary exists if the electric field changes its sign at the opposite side of the grain boundary. The potential barrier does not exist in all grain boundaries in the low doped polycrystalline detector and it never exists in intrinsic polycrystalline detectors under applied bias condition provided there is no charge trapping in the grain.
| Divisions: | Concordia University > Gina Cody School of Engineering and Computer Science > Electrical and Computer Engineering |
|---|---|
| Item Type: | Thesis (Masters) |
| Authors: | Chowdhury, Mazharul Huq |
| Institution: | Concordia University |
| Degree Name: | M.A. Sc. |
| Program: | Electrical and Computer Engineering |
| Date: | 30 September 2010 |
| Thesis Supervisor(s): | kabir, M. Zahangir |
| ID Code: | 7486 |
| Deposited By: | MAZHARUL HUQ CHOWDHURY |
| Deposited On: | 08 Jun 2011 19:58 |
| Last Modified: | 18 Jan 2018 17:30 |
References:
[1 ] G. Zopp , I. Forbes, R. W. Miles, P. J. Dale, J. J. Scragg, and L. M. Peter, “Cu2ZnSnSe4 thin film solar cells produced by Selenisation of magnetron sputtered precursors,” Prog. Photovolt: Res. Appl., vol.17, pp.315-319, 2009.[2] N. E. Hartsough, E. Nygard, N. Malakhov, W. C. Barber, and T. Gandhi, “Polycrystalline mercuric iodide films on CMOS readout arrays,” IEEE Trans Nucl Sci., vol.56, no. 4,pp. 1810–1816, August 2009.
[3] Z. A. Smith, and K. D. Taylor, ”Renewable and alternative energy resources,” ABC-CLIO, Inc., Santa Barbara, California, p.164, 2008.
[4] D. M. Chapin, C. S. Fuller, G. L. Pearson, “A new silicon p-n junction photocell for converting solar radiation into electrical power,” J. Appl. Phys., vol. 25, 676–677, 1954.
[ 5] K. Yu, and J. Chen,“Enhancing solar cell efficiencies through 1-d nanostructures,” Nanoscale Res. Lett., vol. 4, pp.1–10, 2009.
[6] A. M. Acevedo, “Effective absorption coefficient for graded band-gap semiconductors and the expected photocurrent density in solar cells,” Solar Energy Materials & Solar Cells, vol.93, pp.41– 44, 2009.
[ 7] T. Zdanowicz, T. Rodziewicz, M. Zabkowska-Waclawek, “Theoretical analysis of the optimum energy bandgap of semiconductors for fabrication of solar cells for applications in higher latitudes locations,” Solar Energy Materials & Solar Cells, vol. 87, pp. 757–769, 2005.
[8 ] C. H. Henry, “Limiting efficiencies of ideal single and multiple energy gap terrestrial solar cells,” Journal of applied physics B, vol.51, pp. 4494, 1980.
[9 ]Y. Eisen, A. Shor, I. Mardor, “CdTe and CdZnTe gamma ray detectors for medical and industrial imaging systems”, Nuclear Instruments and Methods in Physics Research A, vol.428, pp.158-170, 1999.
[10 ] D. Patidar, K. S. Rathore, N. S. Saxena, K. Sharma, T. P. Sharma, “Energy band gap and conductivity measurement of CdSe thin films,” Chalcogenide Letters, vol. 5, no. 2, pp. 21 – 25, February 2008.
[11 ] S. Del Sordo, L. Abbene, E. Caroli, A. M. Mancini, A. Zappettini and P. Ubertini, “Progress in the development of CdTe and CdZnTe semiconductor radiation detectors for astrophysical and medical applications,” Sensors, vol.9, pp. 3491-3526, 2009.
[12 ] X. Wu, “High-efficiency polycrystalline CdTe thin-film solar cells,” Solar Energy, vol.77, pp. 803–814, 2004.
[ 13] A. M. Acevedo, “Thin film CdS/CdTe solar cells: research perspectives,” Solar Energy, vol.80, pp.675–681, 2006.
[14 ] M. A. Contreras, B. Egaas, K. Ramanathan, J .Hiltner, A. Swartzlander, F. Hasoon and R. Noufi, ” Progress toward 20% efficiency in Cu(In, Ga)Se2 polycrystalline thin film solar cell,” Progress in Photovoltaics: Research and Applications., vol. 7, pp.311-316,1999.
[15 ] M. A .Green, K Emery, Y. Hishikawa, and W. Warta, “Solar cell efficiency tables (version36),” Prog. Photovolt: Res. Appl., vol.18, pp.346–352, June 2010.
[16 ] D. C. Hunt, O. Tousignant, and J. A. Rowlands,“Evaluation of the imaging properties of an amorphous selenium-based flat panel detector for digital fluoroscopy,” Med. Phys., 31, pp. 1166-1175, 2004.
[17 ] K. Suzuki, “Flat panel displays using amorphous and mono-crystalline semiconductor devices,” in Amorphous and Microcrystalline Devices: Optoelectronic devices, edited by J. Kanicki, Boston, MA: Artech House, 1991, Ch. 3.
[18 ] J. A. Rowlands and J. Yorkston, “Flat panel detectors for digital radiography” in Handbook of Medical Imaging Vol. 1, edited by J. Beutel, H. L. Kundel and R. L. Van Metter (SPIE Press, Washington, 2000), Ch. 4.
[19 ] M. J. Yaffe and J. A. Rowlands, “X-ray detectors for digital radiology,” Phys. Med. Biol., vol.42, pp. 1-39, 1997.
[20 ] A. R. Cowen, ”Digital x-ray imaging,” Measurement Science and Technology, vol.2, no.8, August 1991.
[21 ] I. Fujieda, G. Cho, J. Drewery, T. Gee, T. Jing, S. N. Kaplan, V. Perez-Mendez, and D. Widermuth, “X-ray and charged particle detection with CsI(T1) layer coupled to a-Si:H photodiode layers,” IEEE Trans. Nucl. Sci., vol. 38, pp.255-262,1991.
[22 ] S. O. Kasap, and J. A. Rowlands, “Direct-conversion flat-panel x-ray image sensors for digital radiography,” Proc. IEEE, vol. 90, pp. 591-603, 2002.
[23 ] E. Samei, and M. J. Flynn,“An experimental comparison of detector performance for direct and indirect digital radiography systems,” Med. Phys., vol.30, pp. 608-622, 2003.
[ 24]J. M. Boone, “Chapter 1: X-ray production, interaction, and detection in diagnostic imaging”, Handbook of Medical Imaging: Volume 1. Physics and Psychophysics, edited by Beutel J., Kundel H.L., and VanMetter R.L., SPIE Press, Bellington,2000, pp. 1-78.
[25 ] S. O. Kasap, “X-ray sensitivity of photoconductors: application to stabilized a-Se”, Journal of Physics D: Applied Physics, vol.33, pp. 2853-2865, 2000.
[26 ] B. Polischuk, Z. Shukri, A. Legros, and H. Rougeot, “Selenium direct converter structure for static and dynamic x-ray detection in medical imaging,” Proc. SPIE, vol.3336, pp. 494-504, 1998.
[27 ] S. O. Kasap, M. Zahangir Kabir, and J. A. Rowlands,“ Recent advances in x-ray photoconductors for direct conversion x-ray image sensors,” Current Applied Physics, vol.6, pp.288-292, 2006.
[28 ] K. Oh, M. Yun, S. Choa, M. Kim, Y. Kim, Y. Kim, J. Sin, S. Nam, _ “Laminate structure detectors for low dark current with photoconductors in digital x-ray imaging,” Nuclear Instruments and Methods in Physics Research A, vol.607, pp.158–161, 2009.
[29 ] S. O. Kasap and J. A. Rowlands, “X-ray photoconductor and stabilized a-Se for direct conversion digital flat-panel x-ray image detectors,” Journal of Material Science: Materials in Electronics, vol. 11, pp.179-198, 2000.
[30 ] A. Zuck, M. Schieber, O. Khakhan, and Z. Burshtein,“Near single-crystal electrical properties of polycrystalline HgI2 produced by physical vapor deposition,” IEEE Trans. Nucl. Sci., vol. 50, pp. 991-997, 2003.
[31 ] S. Tokuda, H. Kishihara, S. Adachi, and T. Sato, “Improvement of the temporal response and output uniformity of polycrystalline CdZnTe films for high sensitivity x-ray imaging,” Proc. SPIE, vol.5030, pp. 861-870, 2003.
[32 ] R. A. Street, S. E. Ready, K. Van Schuylenbergh, J. Ho, J. B. Boyec, P. Nylen, K. Shah, L. Melekov, and H. Hermon, “Comparison of PbI2 and HgI2 for direct detection active matrix x-ray image sensors,” J. Appl. Phys., vol. 91, pp. 3345-3355, 2002.
[33 ] S. Tokuda, H. Kishihara, S. Adachi, and T. Sato, “Preparation and characterization of polycrystalline CdZnTe films for large area, high sensitivity x-ray detectors: review,” J. Mat. Sci.: Mat. Elec., vol.15, pp. 1-8, 2004.
[34 ] M. Simon, R. A. Ford, A. R. Franklin, S. P. Grabowski, B. Mensor, G. Much, A. Nascetti, M. Overdick, M. J. Powell, and D. U. Wiechert, “PbO as direct conversion x-ray detector material,” Proc. SPIE, vol.5368, pp. 188-199, 2004.
[35 ] S. O. Kasap and J. A. Rowlands, “Direct-conversion flat panel x-ray image detectors,” IEE Proc.-CDS, vol. 149, pp. 85-96, 2002.
[36 ] M. Z. Kabir, S.O. Kasap and J.A. Rowlands, “Photoconductors for x-ray image detectors”, in Springer Handbook of Electronic and Photonic Materials, (Springer, Würzburg, 2006), Ch. 48.
[37 ] H. Du, L. E. Antonuk, Y. El-Mohri, Q. Zhao, Z. Su, J. Yamamoto, and Y. Wang, “Investigation of the signal behavior at diagnostic energies of prototype, direct detection, active matrix, flat-panel imagers incorporating polycrystalline HgI2,” Physics in Medicine and Biology, vol.53, pp. 1325-1351, February 2008.
[38 ] M. Z. Kabir, “Effects of charge carrier trapping on polycrystalline PbO X-ray imaging detectors,” J. Appl. Phys., vol. 104, pp. 1–9, 2008.
[39 ] J. Y. W. Seto,“The electrical properties of polycrystalline silicon films,” Journal of Applied Physics, vol. 46, no. 12, December 1975.
[40 ] F. Greuter, and G. Blatter, ” Electrical properties of grain boundaries in polycrystalline compound semiconductors,” Semiconductor Science and Technology, vol. 5, pp.111-137, February, 1990.
[41 ] Z. Su, L.E. Antonuk, Y. El-Mohri, L. Hu, Hong. Du, A. Sawant, Yixin. Li, Yi. Wang, Jin.Yamamoto and Q. Zhao, ”Systematic investigation of the signal properties of polycrystalline HgI2 detectors under mammographic, radiographic, fluoroscopic and radiotherapy irradiation conditions,” Physics in medicine and biology,vol.50, pp.2907-2928, 2005.
[42 ] M. Schieber, A. Zuck, H. Gilboa, and G. Zentai, “Reviewing Polycrystalline Mercuric iodide x-Ray detectors,” IEEE Transactions on Nuclear Science, vol.53, no.4, 2006.
[43 ] G. Zentai, L. Partain, R. Pavlyuchkova, C. Proano, B. N. Breen, A. Taieb, O. Dagan, M. Schieber, H. Gilboa, and J. Thomas, “Mercuric iodide medical imagers for low exposure radiography and fluoroscopy,” Proc. SPIE, vol. 5368, pp. 200-210, 2004.
[44 ] M. Schieber, A. Zuck, M. Braiman, J. Nissenbaum, R. Turchetta, W. Dulinski,D. Husson, and J.L. Riester, “Novel mercuric iodide polycrystalline nuclear particle counters,” IEEE Transactions on Nuclear Science, vol.44, no.6, pp. 2571-2575, 1997.
[ 45] R. C. Whited and L. V. D. Berg, “Native defect compensation in HgI2 crystals,” IEEE Transactions on Nuclear Science, vol.24, p.165, 1977.
[46 ] G. Zentai, M. Schieber, L. Partain, R. Pavlyuchkova, C. Proano, ”Large area mercuric iodide and lead iodide x-ray detectors for Medical and non-destructive industrial imaging,” Journal of Crystal Growth, vol.275, pp.1327-1331, 2005.
[47 ] M. Schieber, N. Zamoshchik, O. Khakhan, A. Zuck, ”Structural changes during vapor-phase deposition of polycrystalline-PbI2 films,” Journal of Crystal Growth, vol.310, pp.3168–3173, 2008.
[48 ] G. Zentai, L. Partain, R. Pavlyuchkova, C. Proano, G. Virshup, L. Melekhov, A. Zuck, B. N. Breen, O. Dagan, A. Vilensky, M. Schieber, H. Gilboa, P. Bennet, K. Shah, Y. Dmitriev, and J. Thomas, “Mercuric iodide and lead iodide x-ray detectors for radiographic and fluoroscopic medical imaging,” Proc. SPIE, vol.5030, pp. 77-91, 2003.
[49 ] J. F. Condeles, R. A. Ando, M. Mulato, ” Optical and structural properties of PbI2 thin films,” Jouranl of Material Science, vol.43, pp.525-529, 2008.
[50 ] R. A. Street, S. E. Ready, F. Lemmi, K. S. Shah, P. Bennett, and Y. Dmitriyev, “Electronic transport in polycrystalline PbI2 films,” Journal of Applied Physics, vol.86, pp. 2660-2667, 1999.
[51 ]A. Brauers, N. Conrads, G. Frings, U. Schiebel, M.J. Powell, and C. Glasse, “X-ray sensing properties of a lead oxide photoconductor combined with an amorphous silicon TFT array,” Materials Research Society, vol. 50, pp.321–326, 1998.
[52 ] M. Simon, R. A. Ford, A. R. Franklin, S. P. Grabowski, B. Menser, G. Much, A. Nascetti, M. Overdick, M.J. Powell, and D.U. Wiechert, “Analysis of Lead Oxide (PbO) layers for direct conversion x-Ray detection,” IEEE Transactions on Nuclear Science, vol.52, no.5, pp.2035-2040, 2005.
[53 ] S. Irvine, “Solar cells and Photovoltaics,” in Springer Handbook of Electronic and Photonic Materials, (Springer, Würzburg, 2006), Ch. 46.
[54 ] J. H. Won, K. H. Kim, J. H. Suh, S. H. Cho, P. K. Cho, J. K. Hong, and S. U. Kim, “The X-ray sensitivity of semi-insulating polycrystalline CdZnTe thick films, “ Nuclear Instruments and Methods in Physics Research A, vol.591, pp.206-208, 2008.
[ 55 ] R. Decorby, M. Isshiki, J. Wang, “II-IV Semiconductors for optoelectronics: CdS, CdSe, CdTe,” in Springer Handbook of Electronic and Photonic Materials, (Springer, Würzburg, 2006), Ch. 34.
[56 ] K. Kim , S. Cho, J. Suh, J. Won, J. Hong, S. Kim, “Schottky-type polycrystalline CdZnTe x-ray detectors,” Current Applied Physics, vol.9, pp.306–310, 2009.
[57 ] S. H. Wei, S. B. Zhang, A. Zunger, “Effects of Ga addition to CuInSe2 on its electronic, structural, and defect properties,” Appl. Phys. Lett., vol.72 pp.3199-3201, 1998.
[58 ] G. Baccarani, and B. Ricco, “Transport properties of polycrystalline silicon films,” Journal of Applied Physics, vol. 49, no. 11, November 1978.
[59 ] C. H. Seager, “ Grain boundaries in polycrystalline Silicon,” Annual Review of Materials Science, vol. 1,pp. 271-302, August 1985.
[60 ] G. Blatter, and F. Greuter, “Electrical breakdown at semiconductor grain boundaries,” Physical Review B (Condensed Matter), vol. 34, Issue 12, pp.8555-8572, December 15, 1986.
[61 ] S. N. Mohammad, and C. E. Rogers, ”Theory of electrical transport and recombination in polycrystalline semiconductors under optical illumination,” Solid-State Electronics, vol.31, no.7, pp.1157-1167, 1988.
[62 ] W. Shockley , and W.T.Reed, “Statistics of the recombination’s of holes and electrons,” Physical Review, vol.87, no.5, pp.835-842,1952.
[ 63] H. C. Card, and E. S. Yang,“Electronic process at grain boundaries in polycrystalline semiconductors under optical illumination,” IEEE Transactions on Electron Devices, vol. ED-24, no.4, April 1977.
[64 ] P. Panayotatos, and H. C. Card,“Recombination velocity at grain boundaries in polycrystalline Si under optical illumination,” IEEE Transactions on Electron Devices, vol. EDL-1, no.12, December 1980.
[65 ] C. H. Seager,“Temperature dependency of minority carrier recombination velocities at grain boundaries in silicon”, Applied Physics Letters, vol.41, no.9, November 1982.
[66 ] C. H. Seager, “Grain boundary recombination: Theory and experiment in silicon”, Journal of Applied Physics, vol.52, no.6, June 1981.
[67 ] D. P. Joshi,“Carrier recombination at grain boundaries in polycrystalline silicon under optical illumination,” Solid-State Electronics, vol.29, no.1, pp.19-24, 1986.
[68 ] D. P. Joshi, and D. P. Bhatt, “Theory of grain boundary recombination and carrier transport in polycrystalline silicon under optical illumination,” IEEE Transactions on Electron Devices, vol. 37, no.1, January1990.
[ 69] G. Horowitz, M.E. Hajlaoui, “Grain size dependent mobility in polycrystalline organic field-effect transistors,” Synthetic Metals, vol. 122, pp.185-189, 2001.
[70 ] S. A. Kolosov, Y. V. Klevkov, and A. F. Plontnikov, “Electrical properties of fine-grained polycrystalline CdTe,” Semiconductors, vol. 38, no.4, pp. 445-460, 2004.
[71 ] M. A. Matiowsky, and H. C. Card, “Temperature dependence of photoconductivity in polycrystalline semiconductors,” Solar Cells, vol.6, pp.119 – 123,1982.C. CARD
[ 72] J. W. Orton and M. J. Powell, “The hall effect in polycrystalline and powdered semiconductors,” Rep. Prog. Phys., vol. 43, pp. 1263-1307,1980.
[73 ] M. A .Green, K Emery, Y. Hishikawa, and W. Warta, “Solar cell efficiency tables (version 35),” Prog. Photovolt: Res. Appl., vol.18, pp.144–150, 2010.
[74 ] C. A. Dimitriadis, “Influence of grain boundary recombination velocity and grain size on the Minority carrier lifetime in polycrystalline semiconductors,” Solid State Communications, vol.56, no.11, pp. 925-927, 1985.
[75 ] X. Wu, J. Zhou, A. Duda, J. C. Keane, T. A. Gessert, Y. Yan and R. Noufi, “13.9%-efficient CdTe Polycrystalline Thin-film Solar Cells with an Infrared Transmission of 50%,” Prog. Photovolt: Res. Appl., vol.14, pp.235-239, 2008.
[76 ] H. W. Yao, R. B. James, E. Y. Lee, R. W. Olsen, H. Hermon, R. J. Anderson,” Optical studies of the internal electric field distributions, crystal defects, and detector performance of CdZnTe radiation detectors,” Proc. SPIE, vol. 3446, p.169,1998.
[77 ] M. Schieber, H. Hermon, R. A. Street, S. E. Reddy, A. Zuck, A. I .Vilensky , L. Melekhov , R. Shatunovsky, M. Lukach, E. Meerson, Y. Saado, E. Pinkhasy, “Mercuric iodide thick films for radiological x-ray detector,” Proc. SPIE, Vol. 4142, p.197, 2000.
[78 ] H. L. Malm, and M. Martini, "Polarization phenomena in CdTe: Preliminary results," Can. J. Phys., vol. 51, pp.2336-2340, 1973.
All items in Spectrum are protected by copyright, with all rights reserved. The use of items is governed by Spectrum's terms of access.
Repository Staff Only: item control page
Download Statistics
Download Statistics