Structural studies on the phase stability of In$_{1-x}$ Ga $_{x}$N layers*

The In$_{1-x}$ Ga $_{x}$N ternary alloy system has potential for development of high efficiency solar energy conversion and advanced optoelectronic device applications. Ga$_{1-x}$ In $_{x}$N / In$_{1-x}$ Ga $_{x}$N hetero-structures of various compositions can be engineered to the responsive from UV to IR wavelength regime. However, the growth of such ternary In1-xGaxN alloys is challenging due to high lattice mismatch, interfacial fields and phase segregation. This contribution focuses on the phase stability of In$_{1-x}$ Ga $_{x}$N layers grown by `high-pressure chemical vapor deposition (HPCVD). We present the results of the structural and optical studies on the phase stability of In$_{1-x}$ Ga $_{x}$N layers using Raman spectroscopy (RS), X-Ray Diffraction (XRD), Optical Transmission Spectroscopy (OTS) and Atomic Force Microscopy (AFM). The effect of growth parameters and conditions; V/III ratio, growth temperature and precursor injection scheme, on phase segregation of In$_{1-x}$ Ga $_{x}$N layers and on metallic Indium adlayer formation on surfaces are presented. The effects of phase segregation on the surface topography are studied by AFM.