Self-induced MBE-grown InAsP nanowires on Si wafers for SWIR applications

Abstract

InAsP-based nanoheterostructures are in great demand in mid-infrared photonics for telecom and sensing applications. While the vapor–liquid–solid grown nanowires have demonstrated the potential to control the crystal phase and vary the InAsP alloy composition in a wide range, the use of a foreign gold catalyst adversely affects their optoelectronic properties. Here we address the limitations of a catalyst-free approach, revealing that self-induced InAsP nanowires with a high P-content of 49%, greater than that previously reported, can be grown on silicon wafers via solid-source molecular beam epitaxy. The interplay between arsenic and phosphorus incorporation was studied, revealing that an increased phosphorus flux suppresses the nanowire axial growth rate, decreasing the length to diameter aspect ratio. The relationship between the InAsP nanowire composition and crystal structure was studied using transmission electron microscopy and X-ray diffraction reciprocal space mapping. It was found that, for all compositions achieved, nanowires grow in a random hexagonal wurtzite phase. Low-temperature photoluminescence studies and ab initio density functional theory calculations were performed to evaluate the dependence of the bandgap on the structure and composition of the InAsP alloys. Room temperature photoluminescent response at wavelengths as short as 1480 nm was demonstrated, revealing the suitability of grown nanowires for applications in photobiology and remote sensing.