Strain and built-in fields in wurtzite GaN/AlxIn1-xN quantum wells and quantum dots

Strain and built-in fields in wurtzite (WZ) GaN/AlxIn1-xN quantum wells (QWs) and quantum dots (QDs) with piezoelectric (PZ) and spontaneous (SP) polarizations were investigated by using a multi-band effective mass theory. In the case of GaN/AlInN QW structures, the built-in field in the well nearly becomes zero for the QW structure with x = 0.7 while the potential well depth in the conduction band is very small. However, the GaN/AlInN QD structures show that the built-in field in the GaN dot does not become zero in a range of an investigated Al content and the carrier confinement is possible even for the QD structure with x = 0.7. The potential profiles of both QW and QD structures change from type-I to type-II at the Al content of x = 0.7. These results can be used as a design guide for fabrications of QD-based optoelectronic devices with a high emission intensity.