Non-equilibrium GaNAs alloys with band gap ranging from 0.8-3.4 eV

A new alloy system, the GaN1‐xAsx alloys in the whole composition range was successfully synthesized using the non‐equilibrium low temperature molecular beam epitaxy method. The alloys are amorphous in the composition range of 0.17 < x < 0.75 and crystalline outside this region. The amorphous films have smooth morphology, homogeneous composition and sharp, well defined optical absorption edges. The bandgap energy varies in a broad energy range from ∼3.4 eV in GaN to∼0.8 eV at x∼0.85. The reduction of the band gap can be attributed primarily to the downward movement of the conduction band for alloys with x > 0.2, and to the upward movement of the valence band for alloys with x < 0.2. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)