硝酸應用於鍺放光增強機制之研究

Abstract

本論文探討硝酸與鍺反應後，使得光激發光顯著增強的機制。 在本文中，我們針對可能增強放光的機制做了研究，並提出三種可能的機制：表面反射減少使得吸光增加、表面鈍化以及因表面結構的生成使得出光效率增加等。經由能量散射光譜儀分析的結果，表面結構裡的元素組成為鍺和氧，其比例約為一比二。與文獻資料相比，我們認為表面的結構應由二氧化鍺所組成。 由於在矽晶圓上以磊晶成長的鍺的光激發光非常微弱，我們也利用泡硝酸的方式使得表面成長結構，實驗的結果顯示樣本經由硝酸處理後，光激發光也有明顯的增強。 在本文的第三章，我們把硝酸應用在金屬-絕緣體-半導體的發光二極體上，發現經由表面的粗化，使得出光效率增加，電激發光也有顯著的增強。

We have demonstrated that the intensity of the photoluminescence from germanium can be enhanced by more than 10 times after HNO3 treatment. The mechanisms for the enhancement include lower reflectance of the surface, surface passivation and the formation of the surface structure that reduces the effect of the total internal reflection. The elemental composition determined by the EDX shows that ratio of the germanium and oxygen is 1:2 for the surface structure grown on the germanium substrate after HNO3 treatment. Compared to the literature, it is supposed that the structure is composed of GeO2. The technique of the HNO3 treatment on the germanium substrates is also applied on the epitaxial Ge-on-Si substrate and the metal-insulator-semiconductor light-emitting diodes. The results show that the luminescence can be enhanced as well.