Characteristics of 10 periods Superlattice LED with Si0.8Ge0.2 Capping Layer for 1.3～1.5μm Wavelength Operation

1.3～1.5微米操作波長之10層矽鍺超晶格覆蓋層發光二極體的特性研究

10.6665/JLYIT.2013.12.9

彭鈺華(Y. H. Peng)；連元宏(Y. H. Lien)

矽鍺超晶格 ； 矽鍺螢光光譜 ； 矽鍺光電元件 ； 矽鍺光學特性 ； Superlattices ； Luminescence ； Optoelectronic device ； Optical properties

蘭陽學報

12期（2013 / 06 / 01）

9 - 14

英文

在本篇報告中我們展示了Si0.5Ge0.5/Si超晶格發光二極體1.3～1.4微米的室溫電致發光頻譜。為了瞭解矽鍺能帶的結構，我們設計了純矽以及20%矽鍺的覆蓋層的發光二極體結構作為實驗樣品。實驗結果顯示了非常不同的LI特性以及光譜曲線。剛開始，在20%矽鍺的覆蓋層的發光二極體中是由超晶格中價帶對導帶的載子復合。當注入電流增加時，兩個樣品都顯示出來自矽材料與超晶格結構的電致發光。但是矽發光頻譜的強度趨勢與矽層的厚度有關。LI曲線顯示了純矽覆蓋層樣品在主動區有比較少的電子濃度。根據室溫的結果，20%矽鍺覆蓋層的樣品可能在擴散的電子流前端存在一個小的阻擋層。實驗的結果顯示了矽鍺TypeII的能帶結構並因此局部地提高導帶電子濃度使電致發光的效率增加。

In this report, room temperature electro-luminescence at 1.3-1.4 μm from Si0.5Ge0.5/Sisupperlattices light emitting diodes is demonstrated. Two samples with Si and Si0.8Ge0.2 capping layer are show very different characteristics on LI and spectral curves. At the first, the injection current is still low, the Si0.8Ge0.2 capped sample emitted light from supperlattices band to band recombination and type II band offset recombination between Si and Si0.8Ge0.2 for 30K low temperature measurement. When the injection current increase, the two samples show Si and SLs emission. But, the intensity trend is indicated the Si emission intensity depend on its thickness of Si in the two sample. The LI curves reveal the sample with Si capping layer has less electron concentration in the active region. According to the room temperature results, the sample with Si0.8Ge0.2 capping layer has a small barrier in the front of electron current. We have demonstrated the type II between Si and Si0.8Ge0.2 can form a barrier to increasing Si emission intensity.

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