Published online by Cambridge University Press: 05 February 2016
Bandgap energies of the group III-V quaternary alloy semiconductor, cubic AlxGa1−x NyAs1−y , were calculated by means ofthe dielectric method. While only GaN and GaAs are considered to be directtransition type among the four constituent binary compounds of this quaternaryalloy system, the calculation results show that the bandgap energy range coveredin the direct transition regime of this alloy system was further extended to thehigher energy side of GaN as well as to the lower energy sides of GaAs. Theextension to the higher energy side was attributed to the larger direct bandgapof AlN. On the other hand, the extension to the lower energy side was caused bythe large bowing in the bandgap energy between group III nitrides and arsenides.Calculations under lattice matching to Si and GaAs are also presented.