AVS 51st International Symposium
    Semiconductors Wednesday Sessions
       Session SC-WeA

Paper SC-WeA3
Nitrogen Incorporation in GaAsN Films and GaAsN/GaAs Superlattices

Wednesday, November 17, 2004, 2:40 pm, Room 304C

Session: Narrow Gap Semiconductors
Presenter: H.A. McKay, University of Michigan
Authors: H.A. McKay, University of Michigan
M. Reason, University of Michigan
X. Weng, University of Michigan
N. Rudawski, University of Michigan
W. Ye, University of Michigan
V. Rotberg, University of Michigan
R.S. Goldman, University of Michigan
Correspondent: Click to Email
GaAsN and InGaAsN alloys with a few percent N have potential applications in infrared laser diodes, high efficiency solar cells, and other electronic devices. However, as-grown materials often exhibit poor photoluminescence efficiencies and lower than expected carrier concentrations and mobilities. A few studies have suggested that control of N incorporation via ex-situ annealing or superlattice (SL) growth may lead to improved optical and electronic properties. In this work, we are exploring in-situ approaches to controlling N incorporation during the growth of GaAsN films and GaAsN/GaAs SLs. In the case of GaAsN films, we have investigated N incorporation in GaAsN films grown by solid-source molecular beam epitaxy (MBE) using a 10% N@sub 2@/90%Ar or pure N@sub 2@ RF plasma source, with As@sub 2@ or As@sub 4@, and a variety of growth temperatures, Si-doping, and V/III ratios. Nuclear Reaction Analysis and Rutherford Backscattering Spectrometry in channeling and non-channeling conditions reveal significant composition-dependent non-substitutional incorporation of N, presumably as N-N or N-As split interstitials. We find that non-substitutional N incorporation is minimized for films grown at 400@super o@C with pure N@sub 2@, apparently independent of As species, Si-doping, and V/III ratio. In the case of GaAsN/GaAs SLs, we have developed an in-situ approach to prevent incorporation of N into the GaAs barriers of the superlattice, using an independently-pumped plasma source chamber, separated from the MBE via a gate valve. High-resolution x-ray diffraction studies reveal significant improvements in the interface quality for superlattices prepared with the active N flux controlled via the gate valve in comparison with a conventional shuttering approach. The effects of N incorporation on the electrical and optical properties of GaAsN films and GaAsN/GaAs SLs will also be presented. @FootnoteText@ This work is supported by DOE, AFOSR-MURI, NSF-NER, NASA-Lewis, and TRW.