Enhanced growth and photoluminescence properties of SnxN y (x>y) nanowires grown by halide chemical vapor deposition

Abstract

Tin nitride nanowires have been grown by halide chemical vapor deposition via the reaction of Sn with NH4Cl at 425 °C under a steady flow of NH3 using small ramp rates y) with a hexagonal structure, i.e. c=5.193 , a=3.725 . The excitation of the SnxNy NWs with UV light of λ=300 nm at T=300 and 77 K gave a broad photoluminescence (PL) spectrum covering 450750 nm attributed to optical transitions between shallow and deep traps located within the band gap. These traps are most likely related to surface and nitrogen vacancy states. Time correlated, single photon counting PL measurements taken between 450 and 750 nm, showed that the PL decay has a multi-exponential structure, suggesting the existence of complex, non-radiative relaxation paths with relaxation times that are found to become shorter at smaller wavelengths. Finally no significant differences were observed between the PL spectra of the SnxNy and In doped Sn xNy NWs most likely due to the low level of incorporation of In attributed to differences in the ionic radii of In and Sn but also the larger energy and growth temperatures required for the formation of InN bonds. © 2010 Elsevier B.V. All rights reserved.