Hostname: page-component-586b7cd67f-2plfb Total loading time: 0 Render date: 2024-11-28T05:50:29.176Z Has data issue: false hasContentIssue false

Solid-state lighting with wide band gap semiconductors

Published online by Cambridge University Press:  04 December 2014

Faiz Rahman*
Affiliation:
Stocker Center, School of Electrical Engineering and Computer Science, Ohio University, Athens, Ohio 45701, USA
*
*Address all correspondence to Faiz Rahman at [email protected]
Get access

Abstract

Light-emitting diodes (LEDs) made from wide band gap semiconductors, such as gallium nitride, are undergoing rapid development. Solid-state lighting with these LEDs is transforming patterns of energy usage and lifestyle throughout the world.

With solid-state lighting gradually taking over from incandescent and fluorescent lighting, light-emitting diodes (LEDs) are very much the focus of research nowadays. This compact review takes a look at LEDs for lighting applications made from wide band gap semiconductors. A very brief history of electric lighting is included for completeness, followed by a description of blue-emitting LEDs that serve as pump sources for all ‘white’ LEDs. This is followed by a discussion on techniques to extract more light from the confines of LED chips through surface patterning. The thermal management of LEDs is perhaps the most important consideration in designing and using LED-based luminaires. This topic is discussed with regard to recent studies on LED reliability. The very promising development of gallium nitride-on-silicon LEDs is examined next followed by a discussion on phosphors for color conversion in LEDs. LED lighting has positively influenced both upscale and downscale illumination markets worldwide. Its societal impact is examined, with the review concluding with a look at efforts to produce LEDs from zinc oxide – a material that holds much promise for the future of solid-state lighting.

Type
Review
Copyright
Copyright © Materials Research Society 2014 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Rahman, F.: The bright present and brighter future of LED technology. Silicon Chip 26, 1417 (2013).Google Scholar
Fred Schubert, E., Kyu Kim, J., Luo, H., and Xi, J-Q.: Solid-state lighting- a benevolent technology. Rep. Prog. Phys. 69, 30693099 (2006).Google Scholar
Johnstone, B.: Brilliant!: Shuji Nakamura and the Revolution in Lighting Technology (Prometheus Books, New York, 2007).Google Scholar
Maeda, N. and Hirayama, H.: Realization of high-efficiency deep-UV LEDs using transparent p-AlGaN contact layer. Phys. Status Solidi C 10, 15211524 (2013).Google Scholar
Kim, K.H., Fan, Z.Y., Khizar, M., Nakarmi, M.L., Lin, J.Y., and Jiang, H.X.: AlGaN-based ultraviolet light-emitting diodes grown on AlN epilayers. Appl. Phys. Lett. 85, 47774779 (2004).Google Scholar
Shatalov, M., Sun, W., Jain, R., Lunev, A., Hu, X., Dobrinsky, A., Bilenko, Y., Yang, J., Garrett, G.A., Rodak, L.E., Wraback, M., Shur, M., and Gaska, R.: High power AlGaN ultraviolet light emitters. Semicond. Sci. Technol. 29, 084007 (2014).Google Scholar
Zhang, J., Hu, X., Lunev, A., Deng, J., Bilenko, Y., Katona, T.M., Shur, M.S., Gaska, R., and Asif Khan, M.: AlGaN deep-ultraviolet light-emitting diodes. Jpn. J. Appl. Phys. 44, 72507253 (2005).Google Scholar
Zhao, Y., Oh, S.H., Wu, F., Kawaguchi, Y., Tanaka, S., Fujito, K., Speck, J.S., DenBaars, S.P., and Nakamura, S.: Green semipolar (20bar 2bar 1) InGaN light-emitting diodes with small wavelength shift and narrow spectral linewidth. Appl. Phys. Express 6, 062102 (2013).CrossRefGoogle Scholar
Johnson, K., Bousquet, V., Hooper, S.E., Kauer, M., Zellweger, C., and Heffernan, J.: High-power InGaN light emitting diodes grown by molecular beam epitaxy. Electron. Lett. 40, 237239 (2004).Google Scholar
Taguchi, T.: Present status of white LED lighting technologies in Japan. J. Light Visual Environ. 27, 131139 (2003).Google Scholar
Amano, H., Sawaki, N., Akasaki, I., and Toyoda, Y.: Metalorganic vapor phase epitaxial growth of a high quality GaN film using an AlN buffer layer. Appl. Phys. Lett. 48, 353355 (1986).Google Scholar
Amano, H., Kito, M., Hiramatsu, K., and Akasaki, I.: P-type conduction in Mg-doped GaN treated with low-energy electron beam irradiation (LEEBI). Jpn. J. Appl. Phys. 28, L2112 (1989).Google Scholar
Nakamura, S., Iwasa, N., Senoh, M., and Mukai, T.: Hole compensation mechanism of P-type GaN films. Jpn. J. Appl. Phys. 31, 1258 (1992).Google Scholar
Nakamura, S.: Novel metalorganic chemical vapor deposition system for GaN growth. Appl. Phys. Lett. 58, 20212023 (1991).Google Scholar
Rahman, F., Xu, S., Watson, I.M., Kumar Baid Mutha, D., Oxland, R.K., Johnson, N.P., Banerjee, A., and Wasige, E.: Ohmic contact formation to bulk and heterostructure gallium nitride family semiconductors. Appl. Phys. A 94, 633639 (2009).Google Scholar
Weimar, A., Lell, A., Bruderl, G., Bader, S., and Harle, V.: Investigation of low-resistance metal contacts on p-type GaN using the linear and circular transmission line method. Phys. Status Solidi A 183, 169 (2001).Google Scholar
Lewis, L., Maaskant, P.P., and Corbett, B.: On the specific contact resistance of metal contacts to p-type GaN. Semicond. Sci. Technol. 21, 1738 (2006).Google Scholar
Sheu, J-K., Lu, Y.S., Lee, M-L., Lai, W.C., Kuo, C.H., and Tun, C-J.: Enhanced efficiency of GaN-based light-emitting diodes with periodic textured Ga-doped ZnO transparent contact layer. Appl. Phys. Lett. 90, 263511 (2007).Google Scholar
Sun, X.W. and Kwok, H.S.: Optical properties of epitaxially grown zinc oxide films on sapphire by pulsed laser deposition. J. Appl. Phys. 86, 408 (1999).CrossRefGoogle Scholar
Jeon, S-R., Song, Y-H., Jang, H-J., Mo Yang, G., Won Hwang, S., and Son, S.J.: Lateral current spreading in GaN-based light-emitting diodes utilizing tunnel contact junctions. Appl. Phys. Lett. 78, 32653267 (2001).Google Scholar
Wong, W.S., Sands, T., and Cheung, N.W.: Damage-free separation of GaN thin films from sapphire substrates. Appl. Phys. Lett. 72, 599601 (1998).Google Scholar
Wong, W.S., Sands, T., Cheung, N.W., Kneissl, M., Bour, D.P., Mei, P., Romano, L.T., and Johnson, N.M.: Fabrication of thin-film InGaN light-emitting diode membranes by laser lift-off. Appl. Phys. Lett. 75, 13601362 (1999).CrossRefGoogle Scholar
Wong, W.S., Cho, Y., Weber, E.R., Sands, T., Yu, K.M., Kruger, J., Wengrow, A.B., and Cheung, N.W.: Structural and optical quality of GaN/metal/Si heterostructures fabricated by excimer laser lift-off. Appl. Phys. Lett. 75, 18871889 (1999).Google Scholar
Shchekin, O.B., Epler, J.E., Trottier, T.A., Margalith, T., Steigerwald, D.A., Holcomb, M.O., Martin, P.S., and Krames, M.R.: High performance thin-film flip-chip InGaN -GaN light-emitting diodes. Appl. Phys. Lett. 89, 071109 (2006).Google Scholar
Kim, H., Kim, K-K., Choi, K-K., Kim, H., Song, J-O., Cho, J., Hyeon Baik, K., Sone, C., Park, Y., and Seong, T-Y.: Design of high-efficiency GaN-based light emitting diodes with vertical injection geometry. Appl. Phys. Lett. 91, 023510 (2007).Google Scholar
Hsu, S.C., Pong, B.J., Li, W.H., Beechem, T.E. III, Graham, S., and Liu, C.Y.: Stress relaxation in GaN by transfer bonding on Si substrates. Appl. Phys. Lett. 91, 251114 (2007).Google Scholar
David, A., Fujii, T., Sharma, R., McGroddy, K., Nakamura, S., DenBaars, S.P., Hu, E.L., Weisbuch, C., and Benisty, H.: Photonic-crystal GaN light-emitting diodes with tailored guided modes distribution. Appl. Phys. Lett. 88, 061124 (2006).Google Scholar
Cho, H.K., Jang, J., Choi, J-H., Choi, J., Kim, J., Lee, J.S., Lee, B., Choe, Y.H., Lee, K-D., Kim, S.H., Lee, K., Kim, S-K., and Lee, Y-H.: Light extraction enhancement from nanoimprinted photonic crystal GaN-based blue light-emitting diodes. Opt. Express 14, 8654 (2006).Google Scholar
Schnitzer, I., Yablonovitch, E., Caneau, C., Gmitter, T.J., and Scherer, A.: 30% external quantum efficiency from surface textured, thin-film light-emitting diodes. Appl. Phys. Lett. 63, 21742176 (1993).Google Scholar
Na, S-I., Han, D-S., Kim, S-S., Lim, J-H., Kim, J-Y., and Park, S-J.: Surface texturing of p-GaN layer for efficient GaN LED by maskless selective etching, phys. stat. Phys. Status Solidi C 2, 29162919 (2005).Google Scholar
Windisch, R., Rooman, C., Meinlschmidt, S., Kiesel, P., Zipperer, D., Döhler, G.H., Dutta, B., Kuijk, M., Borghs, G., and Heremans, P.: Impact of texture-enhanced transmission on high-efficiency surface-textured light-emitting diodes. Appl. Phys. Lett. 79, 23152317 (2001).Google Scholar
David, A., Benisty, H., and Weisbuch, C.: Optimization of light-diffracting photonic-crystals for high extraction efficiency LEDs. J. Disp. Technol. 3, 133 (2007).Google Scholar
Hong, H-G., Kim, S-S., Kim, D-Y., Lee, T., Song, J-O., Cho, J.H., Sone, C., Park, Y., and Seong, T-Y.: Enhancement of the light output of GaN-based ultraviolet light-emitting diodes by a one-dimensional nanopatterning process. Appl. Phys. Lett. 88, 103505 (2006).Google Scholar
Wierer, J.J., Steigerwald, D.A., Krames, M.R., O’Shea, J.J., Ludowise, M.J., Christenson, G., Shen, Y-C., Lowery, C., Martin, P.S., Subramanya, S., Gotz, W., Gardner, N.F., Kern, R.S., and Stockman, S.A.: High-power AlGaInN flip-chip light-emitting diodes. Appl. Phys. Lett. 78, 33793381 (2001).Google Scholar
Shakya, J., Kim, K.H., Lin, J.Y., and Jiang, H.X.: Enhanced light extraction in III-nitride ultraviolet photonic crystal light-emitting diodes. Appl. Phys. Lett. 85, 142144 (2004).Google Scholar
Oder, T.N., Shakya, J., Lin, J.Y., and Jiang, H.X.: III-nitride photonic crystals. Appl. Phys. Lett. 83, 12311233 (2003).Google Scholar
Choi, Y-S., Hennessy, K., Sharma, R., Haberer, E., Gao, Y., DenBaars, S.P., Nakamura, S., Hu, E.L., and Meier, C.: GaN blue photonic crystal membrane nanocavities. Appl. Phys. Lett. 87, 243101 (2005).Google Scholar
Matioli, E. and Weisbuch, C.: Impact of photonic crystals on LED light extraction efficiency: approaches and limits to vertical structure designs. J. Phys. D: Appl. Phys. 43, 354005 (2010).Google Scholar
David, A., Fujii, T., Moran, B., Nakamura, S., DenBaars, S.P., Weisbuch, C., and Benisty, H.: Photonic crystal laser lift-off GaN light-emitting diodes. Appl. Phys. Lett. 88, 133514 (2006).Google Scholar
Inoue, K. and Ohtaka, K.: Photonic Crystals: Physics, Fabrication and Applications (Springer, Berlin, 2004).Google Scholar
David, A., Fujii, T., Matioli, E., Sharma, R., Nakamura, S., DenBaars, S.P., Weisbuch, C., and Benisty, H.: Omnidirectional light extraction in GaN LEDs using an Archimedean tiling photonic crystal. Proc. SPIE 6115, 61151X (2006).Google Scholar
Kang, S., Ann, S., and Kim, S-M.: Nanostructures in Electronics and Photonics, Rahman, Faiz ed.; Pan Stanford Publications, Singapore, May 2008, ISBN: 978-981-4241-10-6.Google Scholar
Rahman, F. and De La Rue, R.M.: Photonic crystals enable ultra high brightness LEDs. Photonics Spectra 41, 5256 (2007).Google Scholar
Wierer, J.J., Krames, M.R., Epler, J.E., Gardner, N.F., Craford, M.G., Wendt, J.R., Simmons, J.A., and Sigalas, M.M.: InGaN/GaN quantum-well heterostructure light-emitting diodes employing photonic crystal structures. Appl. Phys. Lett. 84, 38853887 (2004).Google Scholar
Achermann, M., Petruska, M.A., Koleske, D.D., Crawford, M.H., and Klimov, V.I.: Nanocrystal-based light-emitting diodes utilizing high-efficiency nonradiative energy transfer for color conversion. Nano Lett. 6, 1396 (2006).Google Scholar
Mueller, A.H., Petruska, M.A., Achermann, M., Werder, D.J., Akhadov, E.A., Koleske, D.D., Hoffbauer, M.A., and Klimov, V.I.: Multicolor light-emitting diodes based on semiconductor nanocrystals encapsulated in GaN charge injection layers. Nano Lett. 5, 1039 (2006).Google Scholar
Rahman, F. and Johnson, N.P.: Generation of white light from optically pumped gallium nitride epilayers. Appl. Phys. Lett. 89, 021105 (2006).Google Scholar
Rahman, F.: Thermal doping of rare-earth ions in gallium nitride. J. Mod. Opt. 55, 10251031 (2008).Google Scholar
Rahman, F.: Lanthanide ion incorporation in gallium nitride through a salt melt process. J. Optoelectron. Adv. Mater. 11, 326330 (2009).Google Scholar
Lee, D.S. and Steckl, A.J.: Room-temperature-grown rare-earth-doped GaN luminescent thin films. Appl. Phys. Lett. 79, 19621964 (2001).Google Scholar
Steckl, A.J. and Zavada, J.M.: Optoelectronic properties and applications of rare-earth-doped GaN. MRS Bull. 24, 3338 (1999).Google Scholar
Piprek, J.: Efficiency droop in nitride-based light-emitting diodes. Phys. Status Solidi A 207, 22172225 (2010).Google Scholar
Ryu, H-Y., Shin, D-S., and Shim, J-I.: Analysis of efficiency droop in nitride light-emitting diodes by the reduced effective volume of InGaN active material. Appl. Phys. Lett. 100, 131109 (2012).Google Scholar
Wang, J., Wang, L., Wang, L., Hao, Z., Luo, Y., Dempewolf, A., Müller, M., Bertram, F., and Christen, J.: An improved carrier rate model to evaluate internal quantum efficiency and analyze efficiency droop origin of InGaN based light-emitting diodes. J. Appl. Phys. 112, 023107 (2012).CrossRefGoogle Scholar
Ni, X., Fan, Q., Shimada, R., Özgür, Ü., and Morkoç, H.: Reduction of efficiency droop in InGaN light emitting diodes by coupled quantum wells. Appl. Phys. Lett. 93, 171113 (2008).Google Scholar
Iveland, J., Martinelli, L., Peretti, J., Speck, J.S., and Weisbuch, C.: Direct measurement of Auger electrons emitted from a semiconductor light-emitting diode under electrical injection: identification of the dominant mechanism for efficiency droop. Phys. Rev. Lett. 110, 177406 (2013).CrossRefGoogle ScholarPubMed
Denault, K.A., Cantore, M., Nakamura, S., DenBaars, S.P., and Seshadri, R.: Efficient and stable laser-driven white lighting. AIP Adv. 3, 072107 (2013).Google Scholar
Horng, R-H., Hong, J-S., Tsai, Y-L., Wuu, D-S., Chen, C-M., and Chen, C-J.: Optimized thermal management from a chip to a heat sink for high-power GaN-based light-emitting diodes. IEEE Trans. Electron Devices 57, 22032207 (2010).Google Scholar
Su, Y-F., Yang, S-Y., Hung, T-Y., Lee, C-C., and Chiang, K-N.: Light degradation test and design of thermal performance for high-power light-emitting diodes. Microelectron. Reliab. 52, 794803 (2012).Google Scholar
Edmond, J., Abare, A., Bergman, M., Bharathan, J., Lee Bunker, K., Emerson, D., Haberern, K., Ibbetson, J., Leung, M., Russel, P., and Slater, D.: High efficiency GaN-based LEDs and lasers on SiC. J. Cryst. Growth 272, 242250 (2004).Google Scholar
Chang, M-H., Das, D., Varde, P.V., and Pecht, M.: Light emitting diodes reliability review. Microelectron. Reliab. 52, 762782 (2012).Google Scholar
Liou, B-H., Chen, C-M., Horng, R-H., Chiang, Y-C., and Wuu, D-S.: Improvement of thermal management of high-power GaN-based light-emitting diodes. Microelectron. Reliab. 52, 861865 (2012).Google Scholar
Horng, R-H., Lin, R-C., Chiang, Y-C., Chuang, B-H., Hu, H-L., and Hsu, C-P.: Failure modes and effects analysis for high-power GaN-based light-emitting diodes package technology. Microelectron. Reliab. 52, 818821 (2012).CrossRefGoogle Scholar
Hwa Choi, J. and Whan Shin, M.: Thermal investigation of LED lighting module. Microelectron. Reliab. 52, 830835 (2012).Google Scholar
Jeng, M-J., Chiang, K-L., Chang, H-Y., Yen, C-Y., Lin, C-C., Chang, Y-H., Lai, M-J., Lee, Y-L., and Chang, L-B.: Heat sink performances of GaN/InGaN flip-chip light-emitting diodes fabricated on silicon and AlN submounts. Microelectron. Reliab. 52, 884888 (2012).Google Scholar
Song, B-M., Han, B., Bar-Cohen, A., Arik, M., Sharma, R., and Weaver, S.: Life prediction of LED-based recess downlight cooled by synthetic jet. Microelectron. Reliab. 52, 937948 (2012).Google Scholar
Mo, C., Fang, W., Pu, Y., Liu, H., and Jiang, F.: Growth and characterization of InGaN blue LED structure on Si(111) by MOCVD. J. Cryst. Growth 285, 312317 (2005).Google Scholar
Feltin, E., Beaumont, B., Laügt, M., de Mierry, P., Vennéguès, P., Lahrèche, H., Leroux, M., and Gibart, P.: Stress control in GaN grown on silicon(111) by metalorganic vapor phase epitaxy. Appl. Phys. Lett. 79, 32303232 (2001).Google Scholar
Strittmatter, A., Krost, A., Straßburg, M., Türck, V., Bimberg, D., Bläsing, J., and Christen, J.: Low-pressure metal organic chemical vapor deposition of GaN on silicon(111) substrates using an AlAs nucleation layer. Appl. Phys. Lett. 74, 12421244 (1999).Google Scholar
Schulze, F., Dadgar, A., Bläsing, J., Hempel, T., Diez, A., Christen, J., and Krost, A.: Growth of single-domain GaN layers on Si(001) by metalorganic vapor-phase epitaxy. J. Cryst. Growth 289, 485488 (2006).Google Scholar
Zhu, D., Wallis, D.J., and Humphreys, C.J.: Prospects of III-nitride optoelectronics grown on Si. Rep. Prog. Phys. 76, 106501 (2013).Google Scholar
Ma, J., Zhu, X., Ming Wong, K., Zou, X., and Lau, K.M.: Improved GaN-based LED grown on silicon(111) substrates using stress/dislocation-engineered interlayers. J. Cryst. Growth 370, 265268 (2013).Google Scholar
Kukushkin, S.A., Osipov, A.V., Bessolov, V.N., Medvedev, B.K., Nevolin, V.K., and Tcarik, K.A.: Substrates for epitaxy of gallium nitride: new materials and techniques. Rev. Adv. Mater. Sci. 17, 132 (2008).Google Scholar
Hageman, P.R., Haffouz, S., Grzegorczk, A., Kirilyuk, V., and Larsen, P.K.: Growth of GaN epilayers on Si(111) substrates using multiple buffer layers. Mater. Res. Soc. Symp. Proc. 693, I3.20.1I3.20.6 (2002).Google Scholar
Rahman, F.: Phosphors – the driving force behind LEDs. Compd. Semicond. 20, 5659 (2014).Google Scholar
Chen, L., Lin, C-C., Yeh, C-W., and Liu, R-S.: Light converting inorganic phosphors for white light-emitting diodes. Materials 3, 21722195 (2010).Google Scholar
Yum, J-H., Seo, S-Y., Lee, S., and Sung, Y-E.: Y3Al5O12:Ce0.05 phosphor coatings on gallium nitride for white light emitting diodes. J. Electrochem. Soc. 150, H47 (2003).Google Scholar
Chen, L., Chu, C-I., and Liu, R-S.: Improvement of emission efficiency and color rendering of high-power LED by controlling size of phosphor particles and utilization of different phosphors. Microelectron. Reliab. 52, 900904 (2012).Google Scholar
Hsu, H-C., Wang, C-J., Ru Lin, H., and Han, P.: Optimized semi-sphere lens design for high power LED package. Microelectron. Reliab. 52, 894899 (2012).Google Scholar
Meneghini, M., Dal Lago, M., Trivellin, N., Mura, G., Vanzi, M., Meneghesso, G., and Zanoni, E.: Chip and package-related degradation of high power white LEDs. Microelectron. Reliab. 52, 804812 (2012).Google Scholar
Wang, J-S., Tsai, C-C., Liou, J-S., Cheng, W-C., Huang, S-Y., Chang, G-H., and Cheng, W-H.: Mean-time-to-failure evaluations of encapsulation materials for LED package in accelerated thermal tests. Microelectron. Reliab. 52, 813817 (2012).Google Scholar
Rahman, F.: Broadband LEDs enhance colour fidelity. Compd. Semicond. 18, 4952 (2012).Google Scholar
Rahman, F.: High color definition lighting with broadband LEDs. Opt. Photonics News 24, 2834 (2013).CrossRefGoogle Scholar
Lu, W., Jia, Y., Zhao, Q., Lv, W., and You, H.: Design of a luminescence pattern via altering the crystal structure and doping ions to create warm white LEDs. Chem. Commun. 50, 26352637 (2014).Google Scholar
Alonso, E., Sherman, A.M., Wallington, T.J., Everson, M.P., Field, F.R., Roth, R., and Kirchain, R.E.: Evaluating rare earth element availability: a case with revolutionary demand from clean technologies. Environ. Sci. Technol. 46, 34063414 (2012).Google Scholar
Kato, Y., Fujinaga, K., Nakamura, K., Takaya, Y., Kitamura, K., Ohta, J., Toda, R., Nakashima, T., and Iwamori, H.: Deep-sea mud in the Pacific Ocean as a potential resource for rare-earth elements. Nat. Geosci. 4, 535539 (2011).Google Scholar
Sun, Q., Andrew Wang, Y., Song Li, L., Wang, D., Zhu, T., Xu, J., Yang, C., and Li, Y.: Bright, multicoloured light-emitting diodes based on quantum dots. Nat. Photonics 1, 717722 (2007).Google Scholar
Zhao, J., Bardecke, J.A., Munro, A.M., Liu, M.S., Niu, Y., Ding, I-K., Luo, J., Chen, B., Jen, A.K-Y., and Ginger, D.S.: Efficient CdSe/CdS quantum dot light-emitting diodes using a thermally polymerized hole transport layer. Nano Lett. 6, 463467 (2006).Google Scholar
Lin, M-T., Ying, S-P., Lin, M-Y., Tai, K-Y., and Chen, J-C.: High power LED package with vertical structure. Microelectron. Reliab. 52, 878883 (2012).Google Scholar
Chen, H.C., Chen, K.J., Lin, C.C., Wang, C.H., Yeh, C.C., Tsai, H.H., Shih, M.H., and Kuo, H.C.: Improvement of lumen efficiency in white light-emitting diodes with air-gap embedded package. Microelectron. Reliab. 52, 933936 (2012).Google Scholar
Fu, H-K., Lin, C-W., Chen, T-T., Chen, C-L., Cho, P-T., and Sun, C-J.: Investigation of dynamic color deviation mechanisms of high power light-emitting diode. Microelectron. Reliab. 52, 866871 (2012).Google Scholar
Tsao, J.Y., Saunders, H.D., Creighton, J.R., Coltrin, M.E., and Simmons, J.A.: Solid-state lighting: an energy-economics perspective. J. Phys. D: Appl. Phys. 43, 354001–1-354001-17 (2010).CrossRefGoogle Scholar
Rahman, F.: Solid-state lighting – a bright future. Electron. World 113, 3035 (2006).Google Scholar
Jang, E., Jun, S., Jang, H., Lim, J., Kim, B., and Kim, Y.: White-light-emitting diodes with quantum dot color converters for display backlights. Adv. Mater. 22, 30763080 (2010).Google Scholar
Bond, M., Aye, L., and Fuller, R.J.: Solar lanterns or solar home lighting systems – community preferences in East Timor. Renewable Energy 35, 10761082 (2010).Google Scholar
Lee Hill, R. and Curtin, K.M.: Solar powered light emitting diode distribution in developing countries: an assessment of potential distribution sites in rural Cambodia using network analyses. Socio-Economic Planning Sciences 45, 4857 (2011).Google Scholar
Mills, E., Gengnagel, T., and Wollburg, P.: Solar-LED alternatives to fuel-based Lighting for night fishing. Energy Sustainable Dev. 21, 3041 (2014).Google Scholar
Mukerjee, A.K.: Comparison of CFL-based and LED-based solar lanterns. Energy Sustainable Dev. 11, 2432 (2007).Google Scholar
Adkins, E., Eapen, S., Kaluwile, F., Nair, G., and Modi, V.: Off-grid energy services for the poor: introducing LED lighting in the Millennium Villages Project in Malawi. Energy Policy 38, 10871097 (2010).Google Scholar
Sastrya, O.S., Kamala Devi, V., Pant, P.C., Prasad, G., Kumar, R., and Bandyopadhyay, B.: Development of white LED based PV lighting systems. Sol. Energy Mater. Sol. Cells 94, 14301433 (2010).Google Scholar
Wong, S.: Overcoming obstacles against effective solar lighting interventions in South Asia. Energy Policy 40, 110120 (2012).Google Scholar
Pode, R.: Solution to enhance the acceptability of solar-powered LED lighting technology. Renewable Sustainable Energy Rev. 14, 10961103 (2010).Google Scholar
Chaurey, A. and Kandpal, T.C.: Solar lanterns for domestic lighting in India: viability of central charging station model. Energy Policy 37, 49104918 (2009).Google Scholar
Chaurey, A. and Kandpal, T.C.: Carbon abatement potential of solar home systems in India and their cost reduction due to carbon finance. Energy Policy 37, 115125 (2009).Google Scholar
Jacobson, A.: Connective power: solar electrification and social change in Kenya. World Dev. 35, 144162 (2007).Google Scholar
Johann Nicholas, N., Franks, G.V., and Ducker, W.A.: The mechanism for hydrothermal growth of zinc oxide. CrystEngComm 14, 12321240 (2012).Google Scholar
Demianets, L.N., Kostomarov, D.V., Kuz’mina, I.P., and Pushko, S.V.: Mechanism of growth of ZnO single crystals from hydrothermal alkali solutions. Crystallogr. Rep. 47, S86S98 (2002).Google Scholar
Zheng, H., Du, X.L., Luo, Q., Jia, J.F., Gu, C.Z., and Xue, Q.K.: Wet chemical etching of ZnO film using aqueous acidic salt. Thin Solid Films 515, 39673970 (2007).Google Scholar
Yoo, D-G., Nam, S-H., Kim, M.H., Jeong, S.H., Jee, H-G., Lee, H.J., Lee, N.E., Hong, B.Y., Kim, Y.J., Jung, D., and Boo, J-H.: Fabrication of the ZnO thin films using wet-chemical etching processes on application for organic light emitting diode (OLED) devices. Surf. Coat. Technol. 202, 54765479 (2008).Google Scholar
Lee, J-M., Kim, K-K., Hyun, C-K., Tampo, H., and Niki, S.: Microstructural evolution of ZnO by wet-etching using acidic solutions. J. Nanosci. Nanotechnol. 6, 33643368 (2006).Google Scholar
Kim, H-K., Bae, J.W., Kim, K.K., Park, S.J., Seong, T-Y., and Adesida, I.: Inductively-coupled-plasma reactive ion etching of ZnO using BCl3-based plasmas and effect of the plasma treatment on Ti/Au ohmic contacts to ZnO. Thin Solid Films 447448, 9094 (2004).CrossRefGoogle Scholar
Ip, K., Baik, K.H., Overberg, M.E., Lambers, E.S., Heo, Y.W., Norton, D.P., and Pearton, S.J.: Effect of high-density plasma etching on the optical properties and surface stoichiometry of ZnO. Appl. Phys. Lett. 81, 35463548 (2002).Google Scholar
Lee, J-M., Chang, K-M., Kim, K-K., Choi, W-K., and Park, S-J.: Dry etching of ZnO using an inductively coupled plasma. J. Electrochem. Soc. 148, G1G3 (2001).Google Scholar
Lim, W., Voss, L., Khanna, R., Gila, B.P., Norton, D.P., Pearton, S.J., and Ren, F.: Dry etching of bulk single-crystal ZnO in CH4/H2-based plasma chemistries. Appl. Surf. Sci. 253, 889894 (2006).Google Scholar
Wang, Z.L.: Novel nanostructures of ZnO for nanoscale photonics, optoelectronics, piezoelectricity, and sensing. Appl. Phys. A 88, 715 (2007).Google Scholar
Dai, L.P., Deng, H., Mao, F.Y., and Zang, J.D.: The recent advances of research on p -type ZnO thin film. J. Mater. Sci.: Mater. Electron. 19, 727734 (2008).Google Scholar
von Wenckstern, H., Benndorf, G., Heitsch, S., Sann, J., Brandt, M., Schmidt, H., Lenzner, J., Lorenz, M., Kuznetsov, A.Y., Meyer, B.K., and Grundmann, M.: Properties of phosphorus doped ZnO. Appl. Phys. A 88, 125128 (2007).Google Scholar
Kaminska, E., Piotrowska, A., Kossut, J., Butkutė, R., Dobrowolski, W., Łukasiewicz, R., Barcz, A., Jakieła, R., Dynowska, E., Przeździecka, E., Aleszkiewicz, M., Wojnar, P., and Kowalczyk, E.: p-type conducting ZnO: fabrication and characterization. Phys. Status Solidi C 2, 11191124 (2005).Google Scholar
Zhao, Z., Liang, H.W., Sun, J.C., Bian, J.M., Feng, Q.J., Hu, L.Z., Zhang, H.Q., Liang, X.P., Luo, Y.M., and Du, G.T.: Electroluminescence from n-ZnO/p-ZnO : Sb homojunction light emitting diode on sapphire substrate with metal -organic precursors doped p-type ZnO layer grown by MOCVD technology. J. Phys. D: Appl. Phys. 41, 195110 (2008).Google Scholar
Shukla, G.: ZnO/MgZnO p -n junction light-emitting diodes fabricated on sapphire substrates by pulsed laser deposition technique. J. Phys. D: Appl. Phys. 42, 075105 (2009).Google Scholar
Dong, X., Zhu, H.C., Zhang, B.L., Li, X.P., and Du, G.T.: ZnO-based homojunction light-emitting diodes fabricated by metal-organic chemical vapor deposition. Semicond. Sci. Technol. 22, 11111114 (2007).Google Scholar
Murai, A., Thompson, D.B., Masui, H., Fellows, N., Mishra, U.K., Nakamura, S., and DenBaars, S.P.: Mega-cone blue LEDs based on ZnO/GaN direct wafer bonding. Phys. Status Solidi C 4, 27562759 (2007).Google Scholar
Bayram, C., Hosseini Teherani, F., Rogers, D.J., and Razeghi, M.: A hybrid green light-emitting diode comprised of n-ZnO/(InGaN/GaN) multi-quantum-wells/p-GaN. Appl. Phys. Lett. 93, 081111 (2008).Google Scholar
Bulashevich, K.A., Evstratov, I.Yu., and Karpov, S.Yu.: Hybrid ZnO/III-nitride light-emitting diodes: modelling analysis of operation. Phys. Status Solidi A 204, 241245 (2007).Google Scholar
Alivov, Ya.I., Kalinina, E.V., Cherenkov, A.E., Look, D.C., Ataev, B.M., Omaev, A.K., Chukichev, M.V., and Bagnall, D.M.: Fabrication and characterization of n-ZnO/p-AlGaN heterojunction light-emitting diodes on 6H-SiC substrates. Appl. Phys. Lett. 83, 47194721 (2003).Google Scholar
Yuen, C., Yu, S.F., Lau, S.P., Rusli, , and Chen, T.P.: Fabrication of n-ZnO:Al∕p-SiC(4H) heterojunction light-emitting diodes by filtered cathodic vacuum arc technique. Appl. Phys. Lett. 86, 241111 (2005).Google Scholar
Kim, J.B., Byun, D., Ie, S.Y., Park, D.H., Choi, W.K., Choi, J-W., and Angadi, B.: Cu-doped ZnO-based p-n hetero-junction light emitting diode. Semicond. Sci. Technol. 23, 095004 (2008).Google Scholar
Ahn, J., Park, H., Mastro, M.A., Hite, J.K., Eddy, C.R. Jr., and Kim, J.: Nanostructured n-ZnO / thin film p-silicon heterojunction light-emitting diodes. Opt. Express 19, 2600626010 (2011).Google Scholar
Chang, C-Y., Tsao, F-C., Pan, C-J., Chi, G-C., Wang, H-T., Chen, J-J., Ren, F., Norton, D.P., Pearton, S.J., Chen, K-H., and Chen, L-C.: Electroluminescence from ZnO nanowire/polymer composite p-n junction. Appl. Phys. Lett. 88, 173503 (2006).Google Scholar
Sun, X.W., Huang, J.Z., Wang, J.X., and Xu, Z.: A ZnO nanorod inorganic/organic heterostructure light-emitting diode emitting at 342 nm. Nano Lett. 8, 12191223 (2008).Google Scholar
Ryu, Y., Lee, T-S., Lubguban, J.A., White, H.W., Kim, B-J., Park, Y-S., and Youn, C-J.: Next generation of oxide photonic devices: ZnO-based ultraviolet light emitting diodes. Appl. Phys. Lett. 88, 241108 (2006).Google Scholar