dc.description.abstract | In this study, the GaN thin films with embedded SiO2 nanorods stripes by epitaxial lateral overgrown (ELOG) technology. According to full-width at half-maximum (FWHM) of X-ray ω-rocking curve of GaN (102) and AFM measurements, the dislocation density of GaN epilayers grown on the SiO2 pattern/GaN template was lower than those of the GaN/sapphire. Thus the etching pits density of the GaN films with embedded SiO2 nanorods stripes can be estimated to be approximately of 3.1 x108 cm-2, which is less than that of the conventional GaN films (5.1x108 cm-2). And the FWHM (275 arcsecs) of the GaN films with embedded SiO2 nanorods stripes was narrower than that (329 arcsecs) of the conventional GaN films. As a result, epitaxial lateral overgrown (ELOG) technology was developed to reduce threading dislocations.
InGaN-based Solar cell devices with embedded SiO2 rods stripes in GaN. The device shows significant improvement in current density from 0.44 to 0.52 mA/cm2 and an increment in conversion efficiency from 0.34% to 0.44%. Compared with conventional solar cell device, the conversion efficiency of solar cell device was enhanced 29%. To further enhance light absorption of the InGaN-based solar cell, a highly reflective SiO2 rods stripes structure was embedded in GaN. The origin for the photocurrent enhancement in the solar cell is related to reflection of light by SiO2 nanorods stripes structure.
The solar cell device with sidewall passivaiton, that with VOC = 1.80 V, conversion efficiency = 0.45 %. Compared with conventional solar cell device, that conversion efficiency was enhanced 2%. The SiO2 was used to passivite dangling bonds on the GaN sidewall with SiO2, that nonradiative recombination and leakage current of solar cell device was reduced.
The mesa height of solar cell device was 840nm, that with JSC = 0.57 mA/cm2, conversion efficiency = 0.48 %. Compared with conventional solar cell device, that JSC was enhanced 11.7%, and conversion efficiency was enhanced 15%. When carrier diffusion length was decreased, JSC increased due to the enhancement of conversion efficiency resulting from the decreasing distance between the p-side and n-side electrodes.
The InGaN-based solar cell device with embedded SiO2 nanorods stripes, that mesa height of solar cell device was 840nm, and then with sidewall passivation. The optimal electrical and optical properties of solar cell with JSC = 0.57 mA/cm2, VOC = 1.90 V, FF = 0.45 and conversion efficiency = 0.48 %. Compared with conventional solar cell device, that conversion efficiency was enhanced 41%.
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