銦奈米粒子埋覆於Al2O3/TiO2抗反射層結構之表面電漿效應以提升矽太陽能電池特性之研究

Photovoltaic Performance Enhancement of Plasmonics Silicon Solar Cell Using Indium Nanoparticles Embedded in Al2O3/TiO2 Layer Structure

林其和(Chi-He Lin)

指導教授 ： 何文章

國立臺北科技大學/電資學院/光電工程系研究所/碩士(2014年)

摘要

本論文透過埋入之金屬奈米粒子產生表面電漿效應（Surface Plasmon Resonance, SPR）應用於矽太陽能電池之特性研究。首先，在矽太陽能電池正面製作奈米尺寸之銦奈米粒子（Indium Nanoparticles, In NPs）於不同厚度二氧化鈦(TiO2)空間層(Space Layer)上，再覆蓋一層氧化鋁薄膜(Al2O3)於銦奈米粒子表面使其形成具有電漿效應之抗反射層薄膜（Plasmonic ARC, PARC），此結構經由入射光照射於雙層抗反射層，內部之金屬粒子激發產生SPR使電場侷域性增加，提升太陽能電池對光的吸收，進而提升太陽能電池之整體光電流(Photocurrent, Iph)及光電轉換效率(Conversion efficiency, η)。
　　本實驗利用旋轉塗佈法(Spin-on Coating)將含磷之薄膜形成在p--Si表面，以900℃磷擴散(Phosphor Diffusion)後在正面形成n+-Si Emitter。Al薄膜於電池背面與鈦(Ti)/鋁(Al)薄膜於正面形成金屬電極，完成裸矽太陽能電池。本研究，在裸矽太陽能電池正面，將銦奈米粒子蒸鍍在10 nm、20 nm、30 nm厚之二氧化鈦空間層上，再將其以氧化鋁薄膜覆蓋並探討金屬奈米粒電漿子在不同厚度二氧化鈦空間層對太陽能電池之影響。最後經由反射率、外部量子效率(External Quantum Efficiency, EQE)、暗電流I-V及照光I-V特性量測，分析其具PARC結構之太陽能電池之光電特性。
　　將前述PARC結構之得知最佳條件應用於已製作之裸矽太陽能電池，並製作一組之太陽能電池未覆蓋銦奈米粒子之雙層反射層(DL-ARC)結構並比較，其中DL-ARC結構太陽能電池，在二氧化鈦厚度為30 nm與氧化鋁薄膜65 nm，其光電流密度提升率為47.7%及轉換效率提升率為59.9%；而PARC結構，在二氧化鈦空間層厚度為10 nm與氧化鋁薄膜65 nm，其中因內部之金屬粒子產生之電漿效應，在變角度量測上獲得證實散射光增加額外光路徑，及抗反射層大幅地降低反射光頻譜，使其光電流密度提升率為54.9%及轉換效率提升率為67.2%。

關鍵字

金屬奈米粒子 ； 表面電漿子 ； 單晶矽太陽能電池 ； 外部量子效率

並列摘要

In this paper, the properties of silicon solar cells using the surface plasmon resonance effects generated through the embedded metal nanoparticles are investigated. First, the nanoscale indium nanoparticles (In NPs) were deposited on the titanium dioxide (TiO2) space layer with various thickness. Then, a layer of aluminum oxide (Al2O3) was coated on In NPs/TiO2, it exhibited a plasmon antireflective coating (PARC). The PARC provide both double anti-reflection and SPR effects to improve the incident photons absorbed in semiconductor as well as to enhance the photocurrent (Iph) and conversion efficiency (η).
The experiment began by using the spin on film (SOF) technique to spin phosphorus-containing liquid source on the p--Si surface, and annealed at 900 ℃ (Phosphorus Diffusion) to obtain a n+-Si Emitter layer. The Al film on the back surface and Ti/Al thin film metal on the front surface were deposited using e-beam evaporation. After isolation etching, the bare solar cell was obtained 3.8-nm thick indium nanoparticles was deposited on the TiO2 with the thickness of 10 nm, 20 nm, 30 nm, respectively, and annealed at 200 ℃ for 30 min. Then a 65-nm Al2O3 layer was deposited on In NPs/TiO2 surface to investigate the metal nanoparticles plasmonic impact on different TiO2 thickness. Finally, the reflectivity, external quantum efficiency (EQE), dark I-V and photovoltaic I-V characteristics of the PARC solar cell are measured and compared.
The photovoltaic performance of PARC structure silicon solar cell and double layer anti-reflective coating (DL-ARC) solar cell, which having a 30-nm TiO2 and a 65-nm Al2O3, were measured and compared. The short-current density enhancement (ΔJsc) of 47.7% (from 24.26 to 35.84 mA/cm2) and the conversion efficiency enhancement of (Δƞ) 52.9% (from 9.47 to 14.48) were obtained for the cell with DL-ARC. However, theΔJsc of 54.9 (from 24.30 to 37.64 mA/cm2) andΔƞ of 67.2% (from 9.48 to 15.85) were achieved for the cell with PARC. In summary, an additional enhancement of about 10% was obtained for the PARC solar cell, compared to the cell with DL-ARC.

並列關鍵字

Metallic Nanoparticles ； Surface Plasmon Resonance ； Solar Cell ； TiO2 Space Layer ； External Quantum Efficiency

參考文獻

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