Highly luminescent InxGa1-xN thin films grown over the entire composition range by energetic neutral atom beam lithography and epitaxy (ENABLE)

In-rich alloys of InxGa1-xN are becoming highly sought after because of the significant role they may play in a number of technologies including photovoltaics, solid-state lighting, and high frequency electronics. Unfortunately, these alloys are difficult to produce with high quality by conventional growth technologies. We describe our efforts to create high-quality In-rich InxGa1-xN alloys by a new growth technology called energetic neutral atom beam lithography and epitaxy (ENABLE). ENABLE uses a collimated beam of neutral N atoms (kinetic energies of ∝2.0 eV) as the reactive group V species in InxGa1-xN growth, allowing for a substantial reduction in substrate growth temperatures (typically 450 C to 750 C). Directly providing a significant portion of the required reaction energy by the N atoms rather than by high substrate temperatures improves InxGa1-xN film quality across the full stoichiometric range. ENABLE-grown InN on sapphire is shown to be highly crystalline by XRD and RBS. The observed photoluminescence (PL) peak energy is 0.74 eV, and the electron concentrations are between 7 x 1018and 7 x 1019 cm-3 with the highest mobility exceeding 1200 cm2/Vs. ENABLE has been used to produce highly luminescent InxGa1-xN with PL peak energies in the 1.5 to 2.5 eV range, spanning the visible range. ENABLE grown InxGa1-xN films are shown by XRD to be highly crystalline consisting of a uniform single phase. These results establish ENABLE as a new technique uniquely capable of low temperature growth of high-quality InxGa1-xN films over widely varying compositions. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)