Numerical Simulation of InGaN Solar Cells with Embedded Metallic Nanoparticles for Efficiency Enhancement

藉由使用三維空間之有限元素法，我們進行埋入奈米粒子造成侷域性表面電漿子及散射效應對於氮化銦鎵太陽電池效率提升之數值研究。論文中使用AM1.5G之太陽光譜作為光源。太陽電池結構上由五個層狀區域所組成，依序是作為表面電極之氧化銦錫透明導電層、n型氮化鎵層、i型氮化銦鎵吸光層、p型氮化鎵層，並使用鋁作為底部電極。我們將銀奈米粒子埋入氮化銦鎵層，藉由侷域性表面電漿子共振及散射之產生，可使高場強分佈於氮化銦鎵層中以提升光吸收。為了計算含銀奈米粒子太陽電池之光吸收與載子傳輸問題，我們利用模擬工具COMSOL來進行三維空間有限元素法之計算。數值模擬結果顯示侷域性表面電漿子之共振可藉由改變奈米粒子尺寸、形狀和週期來調整其共振波長。同樣地，散射效應亦可藉類似方法控制至所需之波長。最後，我們整合出太陽電池因埋入銀奈米粒子之助，整體能量轉換效率大約從10.87 %提升至13.98 %，亦即約有29 %之相對提升。By using the three-dimensional (3D) finite element method, we numerically investigate the localized surface plasmon (LSP) resonance and scattering effects of embedded nanoparticles (NPs) on efficiency enhancement of InGaN solar cells. The light source adopted is the AM1.5G solar spectrum. The solar cell structure consists of five layers, an ITO layer as the top contact, an n-GaN layer, an i-InGaN photoactive layer, a p-GaN layer, and an Al layer as the back contact, respectively. We embed Ag NPs in the InGaN layer, then the generation of LSP resonance and scattering can produce a high field distribution in the InGaN layer for enhancing absorption of light. To calculate the light absorption and carrier transport of the solar cell with Ag NPs, we use the simulation tool COMSOL to realize the 3D finite element method. Through numerical simulation, the results indicate that the LSP resonance can be tuned by changing some parameters of NPs, such as size, shape and period. Also, the scattering effect can be controlled at a desirable wavelength in a similar way. Finally, we investigate the overall power conversion efficiency for the solar cells with aid of the embedded Ag NPs. It can be roughly increased from 10.87 % to 13.98 % with a relative enhancement of 29 %