| Summary: | 碩士 === 國立虎尾科技大學 === 光電與材料科技研究所 === 100 === We have proposed the textured LPD-ZnO grown SiO2 antireflective (AR) layer to enhance the efficiency of GaInP/(In)GaAs/Ge solar cell. Experimental and calculated results indicated that the photocurrent density and conversion efficiency of GaInP/(In)GaAs/Ge solar cell with textured LPD-ZnO on SiO2 AR layer depends on the RMS roughness of LPD-ZnO, which is determined by the HCl concentration and deposition temperature. The optimum RMS roughness range is 90 - 100 nm, which can reduce the reflectivity between air and textured LPD-ZnO effectively. The GaInP/(In)GaAs/Ge solar cell with and 95-nm-thicknes LPD-ZnO on SiO2 AR layer shows a higher open circuit volatge of 2.41 V, short circuit current density of 14.88 mA/cm2, and conversion efficiency of 29.8 % as compared with that with only SiO2 AR layer. It also has a high EQE over the wavelength range from 300 to 1000 nm due to high photocurrent density, resulting from the low reflectivity between air and textured LPD-ZnO. In addition, the temperature characteristics for GaInP/(In)GaAs/Ge solar cell with SiO2 AR layer and with textured LPD-ZnO on SiO2 AR layer are similar, indicating that the solar cell with textured LPD-ZnO cap layer can not degrade with ambient temperature while the solar cell operates outside.
Additionally, aluminum-doped zinc oxide (AZO) grown by dual plasma enhanced metal organic chemical vapor deposition was used to replace the interdigital metal in InGaN / GaN light-emitting diodes (LEDs) to increase the emitting efficiency. Due to the high transparent characteristic of AZO, the light-emitting intensity of InGaN/GaN LEDs with AZO interdigital contact can improve effectively as compared to that with metal contact. In addition, the grating structure composed of AZO / ITO with different refractive index, which results constructive interference of the light-wave, also can enhance the light intensity. The light intensity for InGaN/GaN LEDs with AZO interdigital contact shows an increase of 18.08% as compared to conventional InGaN/GaN LEDs under the driving current of 20 mA.
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