The effects of adjacent dislocations on the electronic and optical properties of GaN/AlN quantum dots

✍ Scribed by A.D Andreev; J.R Downes; E.P O'Reilly

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 123 KB
• Volume: 13
• Category: Article
• ISSN: 1386-9477
• DOI: 10.1016/s1386-9477(02)00311-9

✦ Synopsis

We present a theory of the electronic energy levels and wave functions within GaN quantum dots (QDs), including the e ect of the strain ÿeld of a nearby dislocation and a full treatment of the built-in electrostatic potential. The QD carrier spectra and wave functions are calculated using a plane-wave expansion method within an 8-band k • p model. The GaN QDs are truncated hexagonal pyramids on a wetting layer with an edge dislocation adjacent to each dot. The built-in piezoelectric potential strongly in uences the localization of the carrier wave functions. The potential pushes the electrons to the top of the dot, the holes to the bottom and, additionally, causes strong lateral conÿnement of the carriers near the dot center. The strong lateral conÿnement of the carriers indicates that the e ect of the strain ÿeld due to the dislocation is relatively small. The size of the dot in uences the energies and overlaps, but the presence of the dislocation has minimal e ect. The dependence of the ground state optical transition energy on the size of the dot is in good agreement with experimental data.