||CMES: Computer Modeling in Engineering & Sciences, Vol. 67, No. 2, pp. 79-94, 2010
||Full length paper in PDF format. Size = 4,012,649 bytes
||light emitting diodes (LEDs), density functional theory (DFT), band gap
||This paper describes the quantum mechanical simulation on the photonic properties of group-III nitride clusters, whose bulk types are common materials for light emitting diodes (LEDs). In order to emit different colors of light using the same semiconductor materials, it is possible to vary the band gap by controlling the quantum dot sizes or doping a third atom theoretically. Density functional theory (DFT) calculations are performed to analyze a set of binary (GaN)n(3£n£32) and ternary InxGa1-xN (0£x£0.375) clusters to study their photonic characteristics. The ground state structures are optimized to calculate the binding energies using the time-independent DFT. Then the corresponding density of states (DOS), band gaps, and absorption/excitation energies are evaluated from the time dependent DFT technique. Photoluminescence characteristics are predicted and their relationships with the cluster size and cluster surface effects are studied.