發明
中華民國
099128136
I 416762
同質異相量子井
國立中山大學
2013/11/21
最近計畫主持人羅奕凱(Ikai Lo)教授之實驗室以電漿輔助分子束磊晶系統在鋁酸鋰LiAlO2基板上成長高品質具有纖維鋅礦(Wurtzite)/閃鋅礦(Zinc-blende)/纖維鋅礦(Wurtzite) 結構新穎的氮化鎵(GaN)同質異相量子井材料。GaN一般是以c軸方向成長的wurtzite結構,也就是晶格的排列是以ABABAB…的層狀堆疊而成。我們利用分子束磊晶技術,在成長wurtzite GaN (即N-Ga原子以ABAB…排列)後,將原子排列轉換為ABCABC…的排列模式(即為zinc-blende的結構),如此便將wurtzite的結構轉換為zinc-blende,而在此結構中是以[111]的方向成長。隨後再將其排列模式轉換為ABAB….,如此一來,便可使GaN成長為ABABCABCABABA…的結構,也就是wurtzite/zinc-blende/wurtzite GaN 的結構。另外,wurtzite GaN 的能隙為3.5eV,zinc-blende GaN的能隙為3.2eV,所以在此wurtzite/zinc-blende/wurtzite GaN 中,相同材料的GaN將形成一量子井。高解析穿透式電子顯微鏡下原子尺度的影像,以及選區繞射圖(SAD),可證實該結構的存在情形。另外,陰極射線螢光光譜圖,同時也證實了此元件上具有3.5eV以及3.2eV的能隙。 The self-assembling mechanism of GaN hetero-phased QW is demonstrated, where A, B, and C are identical close-packed N-Ga bi-atom layers. The GaN wurtzite structure is a member of hexagonal close-packed (hcp) crystals stacking in ABABAB. . . layer sequence along c-axis. By employing molecular beam epitaxy technique, the third layer (C layer) can be developed after the first two layers (A, B layers) established. Thus, it is repeatedly constructed with the layer sequence of ABCABCABC . . . to form a face-centered-cubic zinc-blende lattice. In this structure, the direction of zinc-blende GaN development was [111]zb, parallel to[0001]wz, and then the zinc-blende/ wurtzite phase transition will be consequentially established. Therefore, a wurtzite/zinc-blend/wurtzite (ABAB/ABC/ABAB) structure can be formed. In addition, the band gap of wurtzite GaN is 3.5 eV and that of zinc-blende GaN is 3.2 eV, so the hetero-phased GaN form a homo-material quantum well.
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