利用快速熱退火處理方式改善太陽能電池之金屬與薄膜接面電性; Use rapid thermal annealing process to improve the contact between the metal electrode and a-Si:H film of solar cell.

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/46449

Title:	利用快速熱退火處理方式改善太陽能電池之金屬與薄膜接面電性;Use rapid thermal annealing process to improve the contact between the metal electrode and a-Si:H film of solar cell.
Authors:	呂學燁;Hsueh-Yeh Lu
Contributors:	光電科學研究所
Keywords:	非晶矽薄膜;太陽能電池;快速熱退火;a-Si:H film;solar cell;rapid thermal annealing
Date:	2010-11-11
Issue Date:	2011-06-04 15:53:51 (UTC+8)
Publisher:	國立中央大學
Abstract:	氫化非晶矽（a-Si:H）薄膜為一短程有序的結構，具有製程簡單、成本低廉與可大面積製作等特性，因此常被應用於半導體元件和薄膜太陽能電池，然而該材料其晶體結構缺陷較多，故導致非晶矽太陽能電池轉換效率低於結晶矽太陽能電池。針對太陽能電池其結構及材料特性的改善，以有效提升轉換效率為當前重要的研究議題。本實驗主要利用電漿輔助化學氣相沈積系統（Plasma Enhanced Chemical Vapor Deposition, PECVD）製備各層薄膜與太陽能電池（結構為glass/ITO/p-i-n/Ag ）。本實驗主要分為兩個重點討論：一為針對元件內部的多層結構，適度改變本質（i）層厚度以探討太陽光的吸收效應。實驗結果發現厚度在440 nm至620 nm間，以530 nm之 i 層厚度對太陽能電池之吸收（轉換）效率最佳。次為利用快速熱退火（Rapid Thermal Annealing）的製程方式，使金屬電極與非晶矽薄膜間產生歐姆接觸以降低其接面間的電阻，進而改善其電性問題，另外根據文獻指出，非晶矽薄膜經由快速熱退火處理方式可以消除材料表面的懸浮鍵，可將太陽能電池做鈍化處理，以降低載子在表面發生再結合的機率。實驗數據顯示未經過熱退火處理之薄膜與金屬接觸電阻 RC（Contact Resistance）為17.11 kΩ、太陽能電池之串聯電阻 RS（Series Resistance）與並聯電阻 Rsh（Shunt Resistance）分別為170.5 Ω與2232.6 Ω及太陽能電池效率為3.161%；經溫度300oC、時間2分鐘的熱退火製程處理，其接觸電阻 RC與串聯電阻 RS值分別降為6.325 kΩ與114.8 Ω、並聯電阻 Rsh增加為3771.5 Ω，並提升太陽能電池效率至3.784%。 The hydrogenated amorphous silicon (a-Si:H) structure with a short range order; it has simple fabrication process, low cost, and large area. It has been extensively used in semiconductor components and thin film solar cells. However, the conversion efficiency of the a-Si:H solar cell is much lower than the crystalline silicon solar cell due to the much higher defects. Improving the conversion efficiency of a-Si:H solar cells by structures or materials is an important issue. We deposit a-Si:H thin films and corresponding solar cells (with structure of glass/ITO/p-i-n/Ag) by PECVD（Plasma Enhanced Chemical Vapor Deposition, PECVD）. This thesis is divided into two issues. First is the influence of thickness of a-Si:H i layer while the other parameters are kept identical. Because the thickness of i layer decides the absorption of sunlight and electronics properties in the solar cell, we probe the thickness effect of i layer from 440nm to 620nm. We find that the optimized i layer thickness is 530nm. Second, the contact between the metal electrode and a-Si:H film is improved by thermal anneal process in relatively low temperature. The series resistance of solar cells is lower after the thermal anneal process; we conclude that a ohmic contact forms between metal electrode and a-Si:H film. Additionally, the dangling bond at surface of a-Si:H film can be eliminated through the rapid annealing process; the passivation process lowers the recombination rate of free carriers at interfaces. The contact resistance (RC) between the metal electrode and a-Si:H film reduces to 17.11kΩ from 6.325kΩ and the series resistance (RS) of the solar cells reduces to 114.8Ω from 170.5Ω and the shunt resistance (Rsh) of the solar cells increase to 3771.5Ω from 2232.6Ω with the temperature anneal process at 300°C in 2 minutes; meanwhile the conversion efficiency increases to 3.784% from 3.161%.
Appears in Collections:	[Graduate Institute of Optics and Photonics] Electronic Thesis & Dissertation

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