Characterisation of GaAsN layers grown by MOVPE

It has been shown that concentration of nitrogen as low as 0.01 lowers the band gap of the Ga(1-x)In(x)As(1-y)N(y) and Ga(1-x)In(x)P(1-y)N(y) alloy by a significant fraction of eV, showing a "giant" bowing effect. The alloy Ga(1-x)In(x)As(1-y)N(y) with y = 0.35x is lattice-matched to GaAs (or Ge), and this material was used both as active layer for 1 eV laser and as fourth junction Ge lattice-matched in high-efficiency InGaP/GaAs/InGaAsN/Ge multijunction solar cells. The growth of GaAsN and the understanding of its physical properties is a necessary step to control the growth of the quaternary InGaAsN alloy.

Mixed narrow band gap III-V alloys such as GaAsN and InGaAsN are attracting considerable interest for both their fundamental properties and the possibility to use them in novel solar cells for space applications.