GaAsN, a novel material for optoelectronics on silicon

The III-V nitride compounds (GaN, InN, AlN and their alloys) are potential candidates for a new generation of light emitters and other optoelectronic devices, and for high temperature-high power electronics. The major stumbling block that impedes further progress in III-V nitride opto-electronics is the lack of lattice matching between the films and the available substrates. Mismatched heteroepitaxy leads to a high defect density, and it may not be feasible to reduce the defect density by several orders of magnitude unless a lattice-matched material system (substrate+film) is available. To alleviate these problems, it is suggested here that arsenide-nitride alloys, and phosphide-nitride alloys, lattice matched to silicon substrates can be synthesized. These III-V-V' alloys provide a novel material system, exhibiting a direct energy bandgap, heterostructure capabilities, easier doping, contact layers, and patterning opportunities, for the establishment of a robust optoelectronic technology with III-V nitrides on lattice-matched substrates. The arsenide-nitride alloys, and the phosphide-nitride alloys exhibit the zinc blende structure, and a direct bandgap in a large fraction of the composition range. Theoretical calculation of the electronic band structure of GaAsN and AlGaAsN, performed by several groups, resulted in a strong theoretical controversy regarding the bandgap and electro-optic properties of these compounds. This controversy can be resolved by experimental measurements.