Molecular beam epitaxial growth of GaInSbBi for infrared detector applications

The growth of a new quaternary semiconductor alloy GaInSbBi suitable for 8–12 μm infrared detector applications by molecular beam epitaxy is reported for the first time. By the introduction of Ga into the InSbBi alloy, the following have been achieved: (1) enhancement of Bi incorporation, (2) improved lattice-matching to InSb, and (3) suppression of multiple-phase growth and improved surface morphology. The dependence of Bi content and surface morphology on growth temperature and substrate orientation has been investigated. Significant improvement in surface morphology is achieved for films grown on large angle off-axis substrates including (311)A and (511)A. Infrared absorption measurements performed at 77 K indicate that a cutoff wavelength as long as 10.7 μm was achieved. The principles demonstrated in this work are quite general and can be applied to other quaternary material systems containing N, P, As, and Sb such as GaInTlSb and GaInAsN to cover a wide range of band gaps.