Microstructural Evolution and Optical Properties of (InGa)(AsN) Nanostructures Synthesized by Ion Implantation
Abstract
Mixed anion nitride-arsenide compound semiconductor heterostructures are promising for light-emitting devices operating throughout the near infrared range. However, due to the large N-As size difference, a limited miscibility of (InGa)(AsN) on the anion sublattice is predicted. Furthermore, alloy phase separation resulting in the formation of quantum dot-like nanostructures has been reported in GaAsN/GaAs [1] and InGaAsN/GaAs [2] superlattices. We have investigated the evolution of the microstructure and optical properties of (InGa)(AsN) quantum dot-like nanostructures synthesized by N ion implantation into GaAs and InAs, using a variety of implantation and rapid thermal annealing conditions. For 50keV N ion implanted GaAs and InAs substrates, high-resolution cross-sectional transmission electron microscopy reveals ~5 nm diameter amorphous nanostructures surrounded by crystalline matrices. For 100keV N ion implanted GaAs epilayers, ~10 nm diameter crystalline nanostructures surrounded by amorphous matrices are apparent. Electron diffraction indicates that these crystallites are mostly randomly-oriented cubic phases, with lattice parameters close to that of pure GaN. Furthermore, the crystalline nanostructures exhibit significant photoluminescence in the near-infrared range. The apparent lowering of the fundamental band gap is consistent with strain-induced band gap narrowing of a GaN-rich spherical cluster [1]. We will discuss the mechanisms of formation and coarsening of these nanostructures, as well as correlations between their optical and structural properties. [1] R. S. Goldman, R. M. Feenstra, B. G. Briner, M. L. O'Steen, and R. J. Hauenstein, Appl. Phys. Lett. 69, 3698 (1996), J. Electr. Mater. 26, 1342 (1997). [2] H. P. Xin, K. L. Kavanagh, Z. Q. Zhu, and C. W. Tu, Appl. Phys. Lett. 74, 2337 (1999).
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2001
- Bibcode:
- 2001APS..MARJ12004W