Temperature and\nSource Flux Dependence of Light Emission,\nIn Incorporation and Quantum Confinement in Self-Formed Core–Shell\nInGaN Nanowires

We report our recent observations of the growth temperature\nand\nsource flux dependence of the light emission, In incorporation and\nquantum confinement of core–shell InGaN nanowires (NWs), self-formed\nin the growth temperature regime of In desorption by plasma-assisted\nmolecular beam epitaxy on Si(111). For elevated active N flux and\nfor relatively low growth temperatures, the photoluminescence peak\nwavelength and the In incorporation as a function of growth temperature\nexhibit an unexpected maximum. With increasing In/Ga flux ratio, this\nmaximum shifts to lower temperature. Together, the overall In content\nincreases, the photoluminescence shifts to longer wavelengths, the\nIn distribution becomes more uniform and the quantum confinement of\nelectrons and holes in the In-rich nanowire core reduces. A model\nbased on the interplay of thermally activated In desorption with thermally\nactivated In surface diffusion on the nanowire sidewalls accounts\nfor the experimental results for the realization of core–shell\nInGaN nanowires with emission wavelengths tuned to the visible red\nand green and the near-infrared telecom O-band.