AVS 53rd International Symposium
    Electronic Materials and Processing Wednesday Sessions
       Session EM-WeM

Invited Paper EM-WeM10
Atomic Scale Morphology, Growth Behaviour and Thin Film Properties of Ga(In)NAs Quantum Wells

Wednesday, November 15, 2006, 11:00 am, Room 2003

Session: New Directions in Compound Semiconductors
Presenter: T.S. Jones, Imperial College London, UK
Authors: T.S. Jones, Imperial College London, UK
W.M. McGee, Imperial College London, UK
R.S. Williams, Imperial College London, UK
T.J. Krzyzewski, Imperial College London, UK
M.J. Ashwin, Imperial College London, UK
C.P.A. Mulcahy, Cascade Scientific Ltd, UK
Correspondent: Click to Email
Dilute nitride III-V-N semiconductor alloys are attracting considerable interest because of their highly unusual electronic properties and their promise as the active layer in a wide range of (opto)electronic devices. It is widely recognised that the structural and optical quality of Ga(In)NAs quantum wells (QWs) degrades significantly at relatively high N contents further development of this materials system requires a more detailed understanding of the growth behaviour and the effects of alloy composition, layer thickness and different growth conditions. In this talk I will present results from a scanning tunnelling microscopy (STM) study of the atomic-scale morphology and growth behaviour of Ga(In)NAs thin films of different composition grown on GaAs(001) by plasma-assisted molecular-beam epitaxy (MBE). High growth temperatures and N contents lead to significant phase segregation, the formation of large pits and an undulating 3D morphology.@footnote 1,2@ Measurements as a function of film thickness provide insight into the growth behaviour, in particular the onset of phase segregation and surface roughening.@footnote 2@ Spinodal decomposition is believed to facilitate lateral compositional modulation across the film, resulting in a strain-wave oscillating between compressed In-rich regions to tensile N-rich regions. Depending on the magnitude of this strain and the curvature of the resulting strain-wave a range of surface morphologies can result. Low growth temperatures are found to suppress phase segregation for N compositions up to 5% and additional characterisation by photoluminescence spectroscopy, X-ray diffraction, transmission electron microscopy and secondary ion mass spectroscopy indicate that high quality multi-QW layers can be grown with minimal clustering and with controllable emission in the range 1000-1600 nm. @FootnoteText@ @footnote 1@W.M. McGee et al., Appl.Phys.Lett. 87 (2005) 181905@footnote 2@W.M. McGee et al., Surf.Sci.Lett. (2006) submitted.