Structure and strain state of polar and semipolar InGaN quantum dots

摘要: Abstract The nanoscale structural properties of ultrathin (2 nm high) self-assembled (0 0 0 1) polar and ( 1 2 ¯ ) semipolar InGaN/GaN quantum dot (QD) superlattices, grown by plasma-assisted molecular beam epitaxy, were investigated using transmission electron microscopy (TEM) techniques. Samples under two sets temperature ranges compared. higher-temperature uncapped QDs well-defined exhibited a truncated pyramidal morphology. Similar morphology was observed for the embedded QDs, albeit faintly diffused. On other hand, superlattices at lower temperatures heavily distorted due to large stacking fault density. Semipolar lenticular QD found be elastically strained geometrical phase analysis, their strain state well-described biaxial approximation. extrapolated indium content consistent with reduced incorporation efficiency case compared one.