Structure of Isolated Oxygen Impurity States in InN
- PDF / 106,923 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 78 Downloads / 144 Views
1040-Q09-15
Structure of Isolated Oxygen Impurity States in InN Dimiter Alexandrov1, Scott Butcher2, Nikolaus Dietz3, and Hang Yu1 1 Department of Electrical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, P7B5E1, Canada 2 BluGlass Limited, 74 Asquith Street, SILVERWATER, NSW 2128, Australia 3 Department of Physics and Astronomy, Georgia State University, 29 Peachtree Center Avenue, Atlanta, GA, 30302-4106 ABSTRACT The electron state structure of isolated interstitial O atoms in real InN (containing clusters of InN, clusters of InON and clusters of non-stoichiometric InN:In) is the subject of investigation in this paper. It is shown that for the interstitial O atoms the corresponding symmetry is equivalent to that of an O atom in vacuum if the dielectric permittivity of InN is considered, and therefore the hydrogen like impurity atom analysis can be applied for isolated interstitial O atoms hosted in a real InN lattice. It is found that: i) If the O atom is interstitially incorporated in a cluster of pure InN the impurity state has an energy of -5.11 eV, which acts as a donor level with ionization energy +0.06 eV, and also this state is a donor level with an ionization energy of -0.02 eV for a cluster of InON if this cluster occurs at a distance of less than 30 Angstroms; ii) The impurity state has energy -5.15 eV if the O atom is interstitially incorporated in a cluster of InON, which acts as a donor level with ionization energy +0.02 eV, and also this state is a donor level with ionization energy +0.10 eV for a cluster of InN if this cluster occurs on a distance less than 60 Angstroms from the O atom. iii) If the O atom is interstitially incorporated in cluster of non-stoichiometric InN:In the impurity state has energy -5.38 eV, which is in the valence band of this cluster. However this state acts as donor level for both cluster of InN and cluster of InON if they are on distance less that 59 Angstroms from the O atom. The donor ionization energy for the first cluster is +0.33 eV, and for the second cluster it is +0.25 eV. INTRODUCTION Thin films of InN deposited on AlN or sapphire show interesting optical properties with respect to both the optical absorption edge and the maximum of the photo-luminescence spectrum. Both spectral quantities have been observed to show significantly narrower energy intervals, to as low as 0.7 eV, in comparison with the corresponding interval of 1.9 eV long established for InN. These specific features have been the subject of investigation in several papers [1 – 3]. Theoretical investigations of the optical features of InN have been carried out on the basis of InN electron band structure [4, 5]. Oxygen is a common contaminant in InN. There are two possible positions for oxygen atoms in the structure of InN: 1) The oxygen atom can be alloyed to form the ternary compound InOyN1-y where oxygen is substituting on the nitrogen site. 2) The oxygen atom can be an isolated interstitial atom in the InN matrix, or it can be a nonisolated interstitial atom in the same structure
Data Loading...
