GeSbTe硫屬化合物之微結構對太陽能電池的效率研究

Study of The Microstructure for GeSbTe Solar Cell

王聖棻(Sen-Feng Wang)

指導教授 ： 王錫九

國立臺北科技大學/工程學院/材料科學與工程研究所/碩士(2010年)

https://doi.org/10.6841/NTUT.2010.00603

摘要

GeSbTe硫屬化合物已被成熟地應用在光碟媒體儲存上，其結晶與非結晶相二者不同的光學折射率可以用來儲存數位訊號。GeSbTe相變化材料除了具有光學上的特性，也具有優異的電學特性。電性的變化目前已被研究使用在非揮發性記憶體上，施加不同電壓的方式可將GeSbTe相變化材料作可逆式的微結構操作，所得到不同的電阻率亦可用來作為數位訊號的記憶單元。
本研究使用射頻交流濺鍍法來製備GeSbTe化合物薄膜，並將其成功地應用於太陽能電池。GeSbTe化合物薄膜分別使用濺鍍功率 20 W與 30 W的條件下沉積，並以XRD、SEM、UV-Visible光譜儀及Hall量測儀等觀察薄膜之物理及光學特性。濺鍍功率20 W所沉積的薄膜經由熱處理後形成類似GeSb2Te4的結晶相，具有較高的光學穿透率; 濺鍍功率30 W沉積的薄膜經熱處理後形成具有兩種類似Ge2Sb2Te5與GeSb2Te4的結晶相，薄膜結構則具有低的光學穿透率。沉積之薄膜經由熱處理後具有P型半導體特性，可以應用在太陽能電池元件。電池元件為ITO/GST/n-Si/Cr所形成之四層堆疊膜層結構。電池元件在真空環境下熱處理，元件之透明導電電極表面會產生突起物，但在Ar氣氛下的熱處理，突起物有減少的現象。濺鍍功率 20 W之60 nm厚度的GeSbTe薄膜之電池元件，在150℃的熱處理溫度下持溫30分鐘，其電池效率具有最大的效率0.701％。

關鍵字

GeSbTe硫屬化合物 ； 射頻濺鍍 ； Ge2Sb2Te5 ； GeSb2Te4 ； 穿透率 ； 太陽電池 ； 效率

並列摘要

GeSbTe chalcogenides are phase change materials, which have been used as optical disc for media storage because of different refractive index in the crystalline and amorphous phase to distinguish digital signal. Except for the optical properties in material phases, there are distinct electrical properties on controlling the micro-structure of the phase change materials with the applied voltages that have been studied for use in non-volatile memory.
In this study the GeSbTe films are deposited by radio frequency (RF) sputtering system and successfully conducted on the solar cell devices. The GeSbTe films are deposited by RF 20 W and 30 W, which are examined by XRD、SEM、UV-Visible and Hall meter. The deposited films by RF 20 W with heat treatment show GeSb2Te4 crystalline phase and a high penetration of light in visible spectrum. Films deposited by RF 30 W with same heat treatment process exhibit two Ge2Sb2Te5 and GeSb2Te4 crystalline phase, and poor optical properties than the RF 20 W films. The GeSbTe films after heat treatment behave as P type semiconducting materials that can be applied to solar cell. The cell structure is stacked by ITO/GST/n-Si/Cr. Plural protrusions are observed on the transparent conduction electrodes of cell with heating treatment in vacuum that can be restrained with heating treatment in Ar atmosphere. The cell prepared by RF 20 W for 2 minutes sputtering GeSbTe thin film and with heat treatment of 150℃ for 30 minutes has achieved 0.701％ conversion efficiency in its stack-junction solar cell by creating a new base layer.

並列關鍵字

GeSbTe chalcogenides ； RF sputter ； Ge2Sb2Te5 ； GeSb2Te4 ； penetration ； solar cell ； efficiency

參考文獻

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