CHAPTER 5 INGAN-GAN LIGHT-EMITTING DIODE PERFORMANCE IMPROVED BY
5.3 Results and discussions
The dry-etching process is a critical step in the fabrication of nitride-based LEDs. During the ICP etching process, the ICP-damaged layer is a well-known and inevitable problem.[11]
Therefore, the variation in contact between the ICP-etched ITO surface and Cr/Au pad is an important issue. The specific contact resistance (ρc) was examined using the transmission line model (TLM).[12] Five CV-LED samples covered with 2-μm ITO were utilized to study the effect of post-annealing temperature on the ρc (ICP-etched ITO surface). Sample A was untreated, while samples B-E underwent ICP treatment for 10 min. Then, samples C-E were post-annealed
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at 200°C, 400°C and 600°C for 30 min, respectively. Sample B did not undergo any annealing.
TLM gives two relations as follow:
2 SH 2 SK t SH
where RT is the impedance between the two adjacent contact pads, RC is the contact resistance, RSH is the sheet resistance of the semiconductor layer outside the contact region, W is the width of the contact area, L is the distance between two adjacent pads, RSK is the modified sheet resistance under the contact, and Lt is the transfer length. The derived specific contact resistances are shown in Table 5.1. It was found that specific contact resistances of the samples after ICP treatments were smaller than the untreated one (sample A). This was due to the creation of oxygen vacancies during ion bombardment.[13] The ρc increased slightly with post-annealing temperature and reached the maximum value of 7.2 × 10-7 Ω·cm2 at 400°C. This was probably due to the In2O3 aggregation and SnO formation at low temperature, which led to inhomogeneous distribution of Sn, and reduction in carrier concentration.[14] When annealing temperature reached 600°C, crystallites grew and the grain boundary reduced. The tin oxide in the matrix also changed from SnO to SnO2 state.[14] Thus, the ρc reduced to about 1.8 × 10-7 Ω·cm2. From this measurement, it appears that the pad/ITO contact was not deteriorated when the ITO surface was after ICP etching.
The ρc of the interface was even reduced to its minimum when the sample was treated at the post-annealing temperature of the regular device process (600°C).
The surface morphologies of ITO films were examined by scanning electron microscopy (SEM) as shown in Fig. 5.3(a)-(c). The SEM image was taken at an angle of 45° from the perpendicular direction of the surface. A wave-like structure formed on IR-LED was clearly observed. This was caused by the formation of giant folds.[10] During ion bombardment, the
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photoresist layer turned into two distinct layers, which comprised a highly cross-linked polymer top layer modified by the high-energy ions, and a bottom layer of normal resist not affected by ions. As the temperature of the substrate rose, the volatile components evaporating from the bottom layer contributed to the bubble formation. When the tension of the bubble skin reached the limit, it peeled off, and giant folds were formed at the inner area of the initial bubble.[10] The surface morphology of the 1.9-μm-thick photoresist after 4 min etching is shown in Fig. 5.3(d).
This undulation was subsequently transferred to ITO in the same ICP run; and hence, gave the wave-like surface as shown in Fig. 5.3.
The surface of ITO films were also measured by atomic force microscopy (AFM) to determine the degree of texturing as shown in Fig. 5.4. The root mean square (rms) roughness of CV-LED was only 9.19 nm, while that of IR1.6-LED was 122.3 nm. When the photoresist thickness reached 1.9 μm thick, the rms roughness increased to 162.5 nm due to the folds being filled by the melted photoresist.[10] During ICP etching, the substrate temperature rose as a result of thermal accumulation, causing the bottom resist to melt and fill the folds. If the photoresist was thick, there would be much more resist melted and folds would deforminto high undulation structures,[10] which yielded the rougher ITO surface after ICP etching.
I-V characteristics of LEDs are shown in Fig. 5.5. The forward voltages of IR-LEDs were
nearly the same and lay within the range of 3.50-3.55 V (at 20 mA), which were similar to those of CV-LED. These results agreed with the TLM measurement mentioned above. Owing to the creation of oxygen vacancies during ion bombardment, ρc of the sample surfaces still remained small after ICP treatment, hence showing similar I-V characteristics.
The effects of the injection current on luminous intensity are depicted in Fig. 5.6. The emission peak wavelength of the LEDs was 461 nm. The intensity of the two IR-LEDs was higher than that of the CV-LED. The luminance intensity of IR1.9-LED was 71.6 mcd (at 20 mA),
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which was 1.5 times higher than that of the CV-LED, and 1.2 times higher than that of the IR1.6-LED. The light output powers were also shown in Fig. 5.7. LEDs were measured in an integrating sphere. It was found that the IR1.9-LED achieved an output power of 5.75 mW, which was 1.27 times higher than that of the CV-LED, and 1.07 times higher than that of the IR1.6-LED. The improvements in light intensity and output power were predictable because the roughened ITO surface provided the photons multiple opportunities to escape from the LED surface, and redirected the photons.[6]
Fig. 5.8 shows the radiation patterns of the IR-LED with various roughnesses of the ITO layers. The view angle (half-center brightness, which is the angle for 50% of full luminosity) of CV-LED was 138.0°, which was slightly larger than 137.3° and 137.2° of the IR1.6- and IR1.9-LED, respectively. This was because the cone-like surface of the undulation changes the path of photons to the vertical direction of the LED. It was found that the view angle maintained nearly the same with increasing thickness of the PR mask. That is the view angle didn’t change with increasing roughness of ITO layers. This was because the shapes of the cones on surface were the same. As shown in Fig. 5.4, although the surface roughness of the IR1.9-LED was higher than IR1.6-LED, but the slope of the sidewall of the cones didn’t change much. The only difference of the two surfaces is the height of cones.
5.4 Summary
In summary, an investigation of the relationship between ICP etching conditions (photoresist thickness and post-annealing temperature) and LED performance (specific contact resistance, forward voltage, light intensity and output power) has led to the development of a simple, effective natural lithography process for preparing ITO-textured surfaces useful for fabricating
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high-brightness GaN-based LEDs. In this lithography process, photoresist layers (AZ-1518) of different thicknesses (1.6 and 1.9 μm) were used as a mask for ICP dry etching. During etching, surface of the photoresist deformed because of the thermal accumulation, and this undulation was subsequently transferred to ITO surface. It was found that the forward voltages of IR-LEDs were similar to those of the CV-LED. The light intensity and output power of IR-LEDs were better than those of the CV-LED. The luminance intensity of the IR1.9-LED was 71.6 mcd, which was 1.5 times higher than that of the CV-LED, and 1.2 times higher than that of the IR1.6-LED. The IR1.9-LED achieved an output power of 5.75 mW, which was 1.27 times higher than that of the CV-LED, and 1.07 times higher than that of the IR1.6-LED. This is because the roughened ITO surface provided the photons multiple opportunities to escape from the LED surface, and redirected the photons.
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Figure 5.1 Schematic diagrams of the (a) CV-LED, (b) IR-LED.
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Figure 5.2 Experiment flowchart.
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Table 5.1 The specific contact resistance ρc of samples A-E.
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Figure 5.3 SEM images of ITO surfaces: (a) CV-LED, (b) IR1.6-LED, and (c) IR1.9-LED. (d) is the surface morphology of the 1.9-μm-thick photoresist after 4 min ICP etching.
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Figure 5.4 AFM images of ITO surfaces: (a) CV-LED, (b) IR1.6-LED, and (c) IR1.9-LED.
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0 20 40 60 80 100
0 1 2 3 4 5 6
IR1.9-LED IR1.6-LED CV-LED
Voltage (V)
Current (mA)
Figure 5.5 Current-voltage characteristic of the LEDs.
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0 20 40 60 80 100
0 50 100 150 200 250
Luminance Intensity (mcd)
Current (mA)
IR1.9-LED IR1.6-LED CV-LED
Figure 5.6 The effects of injection current on the luminous intensity of the LEDs.
The emission peak wavelength of the LEDs was 461 nm.
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0 20 40 60 80 100
0 5 10 15 20 25
IR1.9-LED IR1.6-LED CV-LED
Pow er (mW)
Current (mA)
Figure 5.7 The effects of injection current on the light output of the LEDs.
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Figure 5.8 Light distribution of LEDs as a function of the detection angle.
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CHAPTER 6
CONCLUSIONS AND FUTURE WORKS
6.1 Conclusions
In this dissertation, we have studied the effect of the silver mirror location on the performance of LEDs. It was found that the light intensity of DRSM-LED was two times higher than that of PR-LED. This enhancement is not surprising, because the Ag mirror redirected the downward-traveling light back to the top surface. By changing the mirror location from the back side of the sapphire to the undoped-GaN/sapphire interface, the LED light intensity was further enhanced. This is because, compared with DRM-LED, the photon path inside the DRSM-LED structure has to pass through an extra bonded interface (adhesive layer/sapphire) two times.
Besides, when the mirror of DRSM-LED redirects the downward-traveling light, light traveling from sapphire to the adhesive layer will only cross within a critical angle of 61.9°. The light reaching the adhesive layer beyond the critical angle will undergo total internal reflection.
In chapter 4, a periodic n-bowl mirror structure was introduced into light-emitting diodes with roughened p-GaN surface (PR-LED) by wafer bonding and laser lift-off technology. The forward voltages of these NBM-LEDs were close to PR-LED, indicating that the transfer method did not change much of the LED structure. The performance of NBM-LEDs was better than that of PR-LED. The luminance intensity of 3-3 NBM-LED at 20 mA was 176.0 mcd, which was 2.33, 1.95, and 1.43 times higher than PR-LED and 25-4 and 4-3 NBM-LEDs. The 3-3 NBM-LED achieved an output power of 6.21 mW, which was 43% larger than the PR-LED, 19%
larger than the 25-4 NBM-LED, and 4% larger than the 4-3 NBM-LED. Besides, the view angle
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decreased with the diameter of n-bowl. The view angle of the PR-LED was 130°. As the diameter of n-bowl decreased to 3 μm, the view angle decreased to 118°. This is because the n-bowl mirror structure acts as a concave mirror. It not only reflects the downward photons to the front side but also redirects the photons which were originally emitted out of the escape cone back into the escape cone.
We also fabricated an InGaN-GaN light emitting diode using a simple natural lithography process to roughen the indium tin oxide window layer. In this lithography process, photoresist layers (AZ-1518) of different thicknesses (1.6 and 1.9 μm) were used as a mask for ICP dry etching. During etching, the surface of the photoresist deformed because of the thermal accumulation, and this undulation was subsequently transferred to the ITO surface. The forward voltages of IR-LEDs were similar to those of the CV-LED. The light intensity and output power of IR-LEDs were better than those of the CV-LED. The luminance intensity of the IR1.9-LED was 71.6 mcd, which was 1.5 times higher than that of the CV-LED and 1.2 times higher than that of the IR1.6-LED. The IR1.9-LED achieved an output power of 5.75 mW, which was 1.27 times higher than that of the CV-LED and 1.07 times higher than that of the IR1.6-LED. This is because the roughened ITO surface provided the photons with multiple opportunities to escape from the LED surface and redirected the photons.
6.2 Future Works
In this dissertation, we proved that the location of mirror indeed affected the performance of LEDs. By changing the mirror location from the back side of the sapphire to the u-GaN/sapphire interface, the LED light intensity was further enhanced. This is because the photon path inside the DRSM-LED structure has to pass through an extra bonded interface (adhesive layer/sapphire)
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two times. Although the photon path inside the DRM-LED structure doesn’t have to pass the extra interface, it still has to cross GaN/adhesive layer interface two times. An ideal situation is to locate the mirror layer on GaN surface. But in order to overcome the total internal reflection, the GaN surface must perform in rough. How to enhance the adhesion between roughened GaN surface and mirror layer could be a challenge.
We also provided another way to adjust the view angle of LEDs in addition to the dome encapsulation. The n-bowl/mirror array not only can redirect photons, but the bowl surface performed in concave shape also can condense photons to the vertical direction of LEDs. The condense phenomena was illustrated by the basic geometry optics, and the change of view angle was confirmed by radiation pattern. To further understand the light path between roughened p-GaN surface and n-bowl array, we think that the simulation is needed in the future.
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REFERENCE
Chapter 1
[1] N. Baldwin, Edison: Inventing the Century, p. 3, Hyperion Books, New York (1995).
[2] A. Zukauskas, M. S. Shurand, and R. Gaska, Introduction to Solid State Lighting, p. 22, John Wiley & Sons, New York (2002).
[3] A. Zukauskas, M. S. Shurand, and R. Gaska, Introduction to Solid State Lighting, p. 6, John Wiley & Sons, New York (2002).
[4] A. Zukauskas, M. S. Shurand, and R. Gaska, Introduction to Solid State Lighting, p. 28, John Wiley & Sons, New York (2002).
[5] S. J. Pearton, GaN and Related Materials, p. 471, Gordon and Breach Science Publishers, New York (1997).
[6] M. Fukuda, Optical Semiconductor Devices, John Wiley & Sons, New York (1999).
[7] H. J. Round, Electrical World, 49, 309 (1907).
[8] O.V. Lossev, Philosophical Magazine Series 7, 6, 1024 (1928).
[9] R. Braunstein, Physical Review, 99, 1892 (1955).
[10] J. I. Pankove, E. A. Miller, and E. Berkeyheiser, J. Luminescence, 5, 84 (1992).
[11] H. Amano, N. Sawaki, I. Akasaki, and Y. Toyoda, Appl. Phys. Lett., 48, 353 (1986).
[12] H. Amano, N. Sawaki, I. Akasaki, and Y. Toyoda, Jpn. J. Appl. Phys., 28, L2112 (1989).
[13] A. Zukauskas, M. S. Shurand, and R. Gaska, Introduction to Solid State Lighting, p. 15, John Wiley & Sons, New York (2002).
[14] S. V. Galginaitis, and G. E. Fenner, Inst. Phys. Conf. Ser., 7, 131 (1968).
[15] M. Berggren, G. Gustafsson, O. Inganas, M. R. Andersson, T. Hjertberg, and O.
96
Wennerstrom, J. Appl. Phys., 76, 7530 (1994).
[16] S. Nakamura, and G. Fasol, The Blue Laser Diode: GaN Based Light Emitters and Lasers, p.
343, Springer, Berlin (1997).
[17] S. Strite, and H. Morkoc, J. Vac. Sci. Technol., B10, 1237 (1992).
[18] H. Morkoc, S. Strite, G. B. Gao, M. E. Lin, B. Sverdlov, and M. Burns, J. Appl. Phys., 76, 1363 (1994).
[19] S. Yoshida, S. Misawa, and S. Gonda, Appl. Phys. Lett., 42, 427 (1983).
[20] H. Amano, I. Akasaki, T. Kozawa, K. Hiramatsu, N. Sawak, K. Ikeda, and Y. Ishi, J. Lumin., 40-41, 121 (1988).
[21] J. A. Vechten, J. D. Zook, and R. D. Horning, Jpn. J. Appl. Phys., 31, 3662 (1992).
[22] S. Nakamura, N. Iwasa, M. Senoh, and T. Mukai, Jpn. J. Appl. Phys., 31, 1258 (1992).
[23] S. Nakamura, Nikkei Electronics Asia, 6, 65 (1994).
[24] S. Nakamura, T. Mukai, and M. Senoh, Appl. Phys. Lett., 64, 1687 (1994).
[25] R. H. Horng, C. E. Lee, C. Y. Kung, S. H. Huang, and D. S. Wuu, Jpn. J. Appl. Phys., 43, L576 (2004).
[26] E. Hecht, Optics, p. 119, Addison Wesley, San Francisco (2002).
[27] I. Schnitzer, E. Yablonovitch, C. Caneau, T. J. Gmitter, and A. Scherer, Appl. Phys. Lett., 63, 2174 (1993).
[28] R. Windisch, B. Dutta, M. Kuijk, A. Knobloch, S. Meinlschmidt, S. Schoberth, P. Kiesel, G.
Borghs, G. H. Dohler, and P. Heremans, IEEE Trans. Electron Devices, 47, 1492 (2000).
[29] C. Huh, K. S. Lee, E. J. Kang, and S. J. Park, J. Appl. Phys., 93, 9383 (2003).
[30] C. F. Lin, Z. H. Yang, J. H. Zheng, and J. H. Dai, IEEE Photonics Technol. Lett., 17, 2038 (2005).
[31] T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, Appl. Phys. Lett.,
97
84, 855 (2004).
[32] W. C. Peng and Y. S. Wu, Appl. Phys. Lett., 88, 181117 (2006).
[33] W. C. Peng and Y. S. Wu, Appl. Phys. Lett., 89, 041116 (2006).
Chapter 2
[1] A. Zukauskas, M. S. Shurand, and R. Gaska, Introduction to Solid State Lighting, p.40, John Wiley & Sons Inc. (2002).
[2] T. Engel, and P. Reid, Quantum Chemistry and Spectroscopy, 73, Benjamin Cummings, San Francisco (2005).
[3] S. H. Han, D. Y. Lee, S. J. Lee, C. Y. Cho, M. K. Kwon, S. P. Lee, D. Y. Noh, D. J. Kim, Y.
C. Kim, and S. J. Park, Appl. Phys. Lett., 94, 231123 (2009).
[4] E. Hecht, Optics, p. 101, Addison Wesley, San Francisco (2002).
[5] E. Hecht, Optics, p. 122, Addison Wesley, San Francisco (2002).
[6] E. Hecht, Optics, p. 119, Addison Wesley, San Francisco (2002).
[7] G. K. Reeves, and H. B. Harrison, IEEE Electron Device Lett., 3, 111 (1982).
[8] Q. Y. Tong, and U. Gosese, Semiconductor Wafer Bonding: Science and Technology, chap. 2, John Wiley & Sons, New York (1998).
[9] W. D. Kingery, H. K. Bowen, and D. R. Uhlmann, Introduction to ceramics, John Weily &
Sons, New York (1976).
Chapter 3
[1] S. Nakamura, S. Senoh, N. Iwasa, and S. Nagahama, Jpn. J. Appl. Phys., Part 2, 34, L797
98
(1995).
[2] H. X. Jiang, S. X. Jin, J. Li, J. Shakya, and J. Y. Lin, Appl. Phys. Lett., 78, 1303 (2001).
[3] R. Windisch, B. Dutta, M. Kuijk, A. Knobloch, S. Meinlschmidt, S. Schoberth, P. Kiesel, G.
Borghs, G. H. Dohler, and P. Heremans, IEEE Trans. Electron Devices, 47, 1492 (2000).
[4] C. Huh, K. S. Lee, E. J. Kang, and S. I. Park, J. Appl. Phys., 93, 9383 (2003).
[5] Y. P. Hsu, S. J. Chang, Y. K. Su, S. C. Chen, J. M. Tsai, W. C. Lai, C. H. Kuo, and C. S.
Chang, IEEE Photonics Technol. Lett., 17, 1620 (2005).
[6] C. M. Tsai, J. K. Sheu, W. C. Lai, Y. P. Hsu, P. T. Wang, C. T. Kuo, C. W. Kuo, S. J. Chang, and Y. K. Su, IEEE Electron Device Lett., 26, 464 (2005).
[7] C. H. Liu, R. W. Chuang, S. J. Changb, Y. K. Su, L. W. Wu, and C. C. Lin, Mater. Sci. Eng.
[12] W. C. Peng and Y. S. Wu, IEEE Photonics Technol. Lett., 18, 613 (2006).
[13] W. C. Peng and Y. S. Wu, Jpn. J. Appl. Phys. Part 2, 45, 7709 (2006).
Chapter 4
[1] H. X. Jiang, S. X. Jin, J. Li, J. Shakya, and J. Y. Lin, Appl. Phys. Lett., 78, 1303 (2001).
99
[2] S. J. An, J. H. Chae, G. C. Yi, and G. H. Park, Appl. Phys. Lett., 92, 121108 (2008).
[3] S. J. An, J. H. Chae, G. C. Yi, and G. H. Park, Appl. Phys. Lett., 92, 121108 (2008).
[4] I. Schnitzer, E. Yablonovitch, C. Caneau, T. J. Gmitter, and A. Scherer, Appl. Phys. Lett., 63, 2174 (1993).
[5] J. S. Lee, J. Lee, S. Kim, and H. Jeon, IEEE Photonics Technol. Lett., 18, 1588 (2006).
[6] C. C. Kao, H. C. Kuo, H. W. Huang, J. T. Chu, Y. C. Peng, Y. L. Hsieh, C. Y. Luo, S. C.
Wang, C. C. Yu, and C. F. Lin, IEEE Photonics Technol. Lett., 17, 19 (2005).
[7] H. Kim, K. K. Choi, K. K. Kim, J. Cho, S. N. Lee, Y. Park, J. S. Kwak, and T. Y. Seong, Opt.
[13] Y. S. Wu and P. W. Huang, Electrochem. Solid-State Lett., 11, J82 (2008).
[14] C. C. Hsiao, C. Y. Peng, and T. S. Liu, Meas. Sci. Technol., 17, 2335 (2006).
[15] D. Halliday, R. Resnick, and J. Walker, Fundamentals of Physics, p. 947, John Wiley &
Sons, New York (2007).
Chapter 5
[1] Q. Dai, M. F. Schubert, M. H. Kim, J. K. Kim, E. F. Schubert, D. D. Koleske, M. H.
Crawford, S. R. Lee, A. J. Fischer, G. Thaler, and M. A. Banas, Appl. Phys. Lett., 94, 111109
100
(2009).
[2] C. C. Kao, H. C. Kuo, H. W. Huang, J. T. Chu, Y. C. Peng, Y. L. Hsieh, C. Y. Luo, S. C.
Wang, C. C. Yu, and C. F. Lin, IEEE Photonics Technol. Lett., 17, 19 (2005).
[3] H. Kim, K. K. Choi, K. K. Kim, J. Cho, S. N. Lee, Y. Park, J. S. Kwak, and T. Y. Seong, Opt.
[8] E. Hecht, Optics, p.119, A. Wesley, San Francisco (2002).
[9] S. J. Chang, S. C. Chen, Y. K. Su, R. W. Chung, W. C. Lai, C. H. Kuo, Y. P. Hsu, Y. C. Lin, S. C. Shei, H. M. Lo, J. C. Ke, and J. K. Sheu, IEEE Photonics Technol. Lett., 16, 1002 (2004).
[10] G. K. Vinogradov and V. M. Menagarishvili, J. Vac. Sci. Technol. B, 17, 95 (1999).
[11] X. A. Cao, H. Cho, S. J. Pearton, G. T. Dang, A. P. Zhang, F. Ren, R. J. Shul, L. Zhang, R.
Hickman, and J. M. Van Hove, Appl. Phys. Lett., 75, 232 (1999).
[12] G. K. Reeves and H. B. Harrison, IEEE Electron Device Lett., 3, 111 (1982).
[13] N. G. Deshpande, A. A. Sagade, S. D. Chavhan, J. C. Vyas, F. Singh, A. K. Tripathi, D. K.
Avasthi, and R. Sharma, Vacuum, 82, 39 (2007).
[14] C. H. Yang, S. C. Lee, S. C. Chen, and T. C. Lin, Mater. Sci. Eng. B, 129, 154 (2006).
簡歷表
個人資料
姓名：廖崢 性別：男
出生日期：1977年12月15日
地址：苗栗縣頭份鎮花園三街51號
學歷
1997年9月～2001年6月 國立中正大學化學工程學系
2001年9月～2003年6月 私立元智大學化學工程與材料科學所 碩士班 2003年9月～2010年1月 國立交通大學材料科學與工程所 博士班
研究項目
表面微結構對氮化鎵發光二極體光電特性之影響
著作目錄
[1] YewChung Sermon Wu, Cheng Liao, and Wei Chih Peng, “Effect of the Silver Mirror Location on the Luminance Intensity of Double-Roughened GaN Light-Emitting Diodes,”
Electrochem. Solid-State Lett., 10, J126 (2007).
[2] Cheng Liao, and YewChung Sermon Wu, “Improved Performance of InGaN-GaN Light-Emitting Diode by a Periodic n-Bowl Mirror Array,” Electrochem. Solid-State Lett., 12, J77 (2009).
[3] Cheng Liao, and YewChung Sermon Wu, “InGaN-GaN Light Emitting Diode Performance Improved by Roughening Indium Tin Oxide Window Layer via Natural Lithography,”
Electrochem. Solid-State Lett., 13, J8 (2010).
[4] Yewchung Sermon Wu and Cheng Liao, “Improved Luminance Intensity of InGaN-GaN Light-Emitting Diode by Roughening both p-GaN and Undoped-GaN Surfaces and Applying a Mirror to the Sapphire Substrate Surface,” ECS Trans., 6, 201 (2007).
[5] Cheng Liao and Yewchung Sermon Wu, “High Performance GaN-based Light-emitting Diodes with Geometric GaN Shaping Structure,” ECS Trans., 16, 223 (2008).
[6] Po Chun Liu, Cheng Liao, and YewChung Sermon Wu, “Wafer Bonding for the Growth of the Heteroepitaxy,” 中國材料科學學會論文集,新竹,11月16日 (2004).
[7] 廖崢,張郁香,彭韋智,吳耀銓,蔡政達, “利用晶圓接合技術將GaN薄膜轉移至Si基板之研 究,” 中國材料科學學會論文集, 台北, 11月25日 (2005).