K.S.A. Butcher, M. Wintrebert-Fouquet, Motlan, S.K. Shrestha, H. Timmers, K.E. Prince, T.L. Tansley
The band-gap of indium nitride has long been believed to be about 1.9eV with slight variations due to band-tailing in polycrystalline samples and degenerate doping. Recently, other values as low as 0.7 eV have apparently been observed. We have compared samples spanning this apparent range of band-gap using secondary ion mass spectroscopy (SIMS), X-ray Photoelectron Spectroscopy (XPS) and heavy ion elastic recoil detection analysis (ERDA), in conjunction with spectral optical density measurements. Once structural inhomogeneiteies are taken into account, we show that much of the conflicting data are compatible with direct photoionisation with a threshold energy of about 1.0eV. This feature was first reported in polycrystalline indium nitride over 15 years ago and attributed to a |p> like defect state. We ask whether the feature may instead be a direct band-gap.
Physics Department, Macquarie University, Sydney, NSW 2109, Australia; Department of Physics, Faculty of Mathematics and Science, State University of Medan, Medan, Indonesia; School of Physics, University of New South Wales, Australian Defence Force Academy, Canberra, ACT 2600, Australia; Department of Nuclear Physics, Res. Sch. of Physical Sci. and Eng., Australian National University, Canberra, ACT 0200, Australia; Australian Nuc. Sci. Technol. Org., Menai, NSW 2234, Private Mail Bag 1, Australia
