當所成長的兩種異質結構材料氮化鎵(GaN)/氮化銦鎵(InGaN)的晶格常數不匹配時,樣品會有應力的累積,隨著成長的厚度愈厚時,所累積的應力也就愈大,當樣品成長至超過某一個臨界厚度(critical thickness, tc)時,樣品無法再承受此應力作用時,則會以形變的方式來釋放應力。因此在成長各種不同的氮化鎵/氮化銦鎵異質材料結構時,可利用X-ray觀察其不同結構方式對應變之影響。氮化銦鎵成長氮化鎵薄膜承受雙軸的壓縮應力,晶格間的不匹配所產生的應力作用,使得在量子井中有壓電場(piezoelectric field)的產生。在成長氮化銦鎵薄膜的過程中,當銦含量愈高時所產生的壓電場也就愈大,對晶體結構的影響也就愈大。本論文中將特別就氮化銦鎵/氮化鎵多層量子井中,應力作用對晶體結構所造成的影響並以倒置空間X-ray繞射方式將其變化加以探討。
In this paper, we describe the effect in GaInN/GaN heterostructures and QW structures. When the GaInN/GaN lattice mismatch generally causes the biaxial strain in the strained layer coherently grown on the lattice-mismatched underlying layer. InN molar fraction considering the strain effect. An enhanced strain relaxation was observedwith In content increased ineach layer. We start with the structural and optical properties of GaInN / GaN heterostructures. Here, reciprocal space mapping (RSM) measurements around asymmetrical diffraction was be used. All of the sample showed the same evidence of this coherent growth. As the result of the RSM data, we can conclude that the relaxation mechanism, such as the generation of the stress, should exist in the strained GaInN layer.