ABSTRACT Fast response time UV photoconductive detector was fabricated based on ZnO film prepared by thermal chemical spray pyrolysis technique. The ZnO nanofilms are grown on the porous silicon (PS) nanosurface which has drastically reduced the response time of the ZnO UV detector from few seconds to few hundreds of microseconds. The surface functionalization of the ZnO film deposited on porous silicon (PS) layer by polyamide nylon has highly improved the photoresponsivity of the detector to 0.8 A/W. The normalized de-tectivity (D*) of the fabricated ZnO UV detector at wavelength of 385 nm is found to be about 2.12 × 1011 cm Hz1/2 W–1. The ZnO film grown on the porous silicon layer was oriented in the c-axis and it is found to be a p-type semiconductor, which is referred to the compensation of the excess charge carriers in the ZnO film by the nanospikes silicon layer.
Cite this paper
nullH. Thjeel, A. Suhail, A. Naji, Q. Al-zaidi, G. Muhammed and F. Naum, "Fabrication and Characteristics of Fast Photo Response ZnO/Porous Silicon UV Photoconductive Detector," Advances in Materials Physics and Chemistry, Vol. 1 No. 3, 2011, pp. 70-77. doi: 10.4236/ampc.2011.13012.
 L. Luo, Y. F. Zhang, S. S. Mao and L. W. Lin, “Fabrication and Characterization of ZnO Nanowires Based UV Photodiodes,” Sensors and Actuators A, Vol. 127, No. 2, 2006, pp. 201-206. doi:10.1016/j.sna.2005.06.023
 E. Monroy, F. Omnes and F. Calle, “Wide-Bandgapsemiconductor Ultraviolet Photodetectors,” Semiconductor Science and Technology, Vol. 18, No. 4, 2003, pp. 33-51.
 A. Müller, G. Konstantinidis, M. Dragoman, D. Neculoiu, A. Dinescu, M. Androulidaki, M. Kayambaki, A. Stavrinidis, D. Dascalu and A. Kostopoulos, “Ultraviolet Msm Photodetector Based on Gan Micromachin-ing,” Applied Optics, Vol. 47, 2008, pp. 1453-1456.
 S. J. Young, L. W. Ji, S. J. Chang and Y. K. Su, “ZnO Metal-Semiconductor―Metal Ultraviolet Sensors with Various Contact Electrodes,” Journal of Crystal Growth, Vol. 293, No. 1, 2006, pp. 43-47.
 J. H. He. Yen H. Lin, M. E. McConney, V. V. Tsukruk and Z. L. Wang, “Enhancing UV Photoconductivity of ZnO Nanobelt by Polyacrylonitrile Functionalization,” Journal of Applied Physics, Vol. 102, No. 8, 2007, p. 084303. doi:10.1063/1.2798390
 X. G. Zheng, Q. Sh. Li, J. P. Zhao, D. Chen, B. Zhao, Y. J. Yang and L.Ch. Zhang, “Photoconductive Ultraviolet Detectors Based on ZnO Films,” Applied Surface Science, Vol. 253, No. 4, 2006, pp. 2264-2267.
 A. Ievtushenko, G. Lashkarev, V. Lazorenko, V. Karpyna, V. Sichkovskyi, L. Ko-syachenko, V. S. rchuk, O. Klyarchuk, V. Bosy, F. Korzhinski, A. Ulyashin, V. Khranovskyy and R. Yakimova, “Ultraviolet Detectors Based on ZnO:N Thin Films with Different Contact Structures,” Acta Physica Polonica A, Vol. 114, No. 5, 2008, pp. 1123-1129.
 K. W. Liu, J. G. Ma, J. Y. Zhang, Y. M. Lu, D. Y. Jiang, B. H. Li, D. X. Zhao, Z. Z. Zhang, B. Yao and D. Z. Shen, “Ultraviolet Photoconductive Detector with High Visible Rejection and Fast Photoresponse Based on ZnO Thin Film,” Solid-State Electronics, Vol. 51, No. 5, 2007, pp. 757-761. doi:10.1016/j.sse.2007.03.002
 Z. Bi, J. W. Zhang, X. M. Bian, D. Wang, X. N. Zhang, W. F. Zhang and X. Hou, “A High-Performance Ultraviolet Photoconductive De-tector Based on a ZnO Film Grown by RF Sputtering,” Journal of Electronic Materials, Vol. 37, No. 5, 2008, pp. 760-763.
 Q. A. Xu, J. W. Zhang, K. R. Ju, X. D. Yang and X. Hou, “ZnO Thin Film Photocon-ductive Ultraviolet Detector with Fast Photoresponse,” Journal of Crystal Growth, Vol. 289, No. 1, 2006, pp. 44-47.
 C. S. Lao, M.-C. Park, Q. Kuang, Y. L. Deng, A. K. Sood, D. L. Polla and Z. L. Wang, “Giant Enhancement in UV Response of ZnO Nanobelts by Polymer Surface-Func- tionalization,” Journal of American Chemical Society, Vol. 129, No. 40, 2007, pp. 12096-12097.
 J. Zhou, Y. D. Gu, Y. F. Hu, W. J. Mai, P.-H. Yeh, G. Bao, A. K. Sood, D. L. Polla and Z. L. Wang, “Gigantic Enhancement in Response and Reset Time of ZnO UV Nanosensor by Utilizing Schottky Contact and Sur-face Functionalization,” Applied Physics Letters, Vol. 94, No. 19, 2009, pp. (191103-1)-(191103-3).
 M. Suhail, E. K. Hassan, S. S. Ahmed and M. K. M. Alnoori, “Improvement of the Photore-ponse of the Solar Blind ZnO Photoconductive UV Detector,” Journal of Electron Devices, Vol. 8, 2010, pp. 268-274.
 L.-C. Chen and C.-N. Pan, “P-ZnO/n-Si Photo-diodes Prepared by Ultraviolet Spraying Pyrolysis Method,” The Open Crystallography Journal, Vol. 1, 2008, pp. 10-13.
 G. Smetad, M. Kunst and C. Vial, “Photovoltaic Response in Electrochemically Pre-pared Photoluminescent Porous Silicon,” Solar Energy Materi-als and Solar Cells, Vol. 26, No. 4, 1992, pp. 277-283.
 W. T. Hsieh, Y. K. Fang, K. H. Lee, J. J. Ho and C. W. Ho, “Using Porous Silicon as SiC High Temperature Optical-Sensing Devices,” IEEE Transactions on Electron Devices, Vol. 48, No. 4, 2001, pp. 801-803.
 D. C. Monroy, J. F. S’anchez-Ram’?rez, M. Herrera- Zald’?var and U. Pal, “Effects of Deposition Parameters on the Optical and Microstructural Characteristics of Sputtered Deposited Nanocrystalline ZnO Thin Films,” Revista Mexicana de F’isica, Vol. S53, No. 5, 2007, pp. 23-28.
 C. Soci, A. Zhang, B. Xiang, S. A. Dayeh, D. P. R. Aplin, J. Park, X. Y. Bao, Y. H. Lo and D. Wang, “ZnO Nanowire UV Photodetector with High Internal Gain,” Nano Letters, Vol. 7, No. 4, 2007, pp. 1003-1009.
 H. Cai, H. L. Shen, Y. G. Yin, L. F. Lu, J. C. Shen and Z. X. Tang, “The Effects of Porous Sili-con on the Crystalline Properties of ZnO Then Film,” The Journal of Physics and Chemistry of Solids, Vol. 70, No. 6, 2009, pp. 967-971. doi:10.1016/j.jpcs.2009.05.004
 D. Vanmaekelbergh and P. Liljeroth, “Electron-Con- ducting Quantum Dot Solids: Novel Materials Based on Colloidal Semiconductor Nanocrystals,” Chemical Society Reviews, Vol. 34, No. 4, 2005, pp. 299-312.
 R. D. Schaller and V. I. Kliwov, “High Efficiency Carrier Multiplication in PbSe Nanocrystals: Implications for Solar Energy Conversion,” Physical Review Letters, Vol. 92, No. 18, 2004, pp. (186601-1)-(186601-4).
 V. I. Klimov, “Mechanisms for Photogeneration and Recombination of Multiexcitions in Semiconductor Nano- crystals: Implications for Lasing and Solar Energy Conversion,” The Journal Physical Chemistry B, Vol. 110, No. 34, 2006, pp. 16827-16845.
 M. Razeghi and A. Rogalski, “Semiconductor Ultraviolet Detectors,” The Journal of Applied Physics, Vol. 79, No. 10, 1996, pp. 7433-7470.