Band Anticrossing in III-N-V Alloys

Recent high hydrostatic pressure experiments have shown that incorporation of small amounts of nitrogen into conventional III–V compounds to form III–N–V alloys leads to splitting of the conduction band into two subbands. The downward shift of the lower subband edge is responsible for the observed, large reduction of the fundamental band gaps in III–N–V alloys. The observed effects were explained by an anticrossing interaction between the conduction band states close to the center of the Brillouin zone and localized nitrogen states. The interaction leads to a change in the nature of the fundamental from the indirect gap in GaP to a direct gap in GaNP. The predictions of the band anticrossing model of enlarged electron effective mass and enhanced donor activation efficiency were confirmed by experiments in GaInNAs alloys.