The work significantly optimizes growth parameters for nanostructured and flat GaN film in the 480-830 °C temperature range. The growth of ordered, high quality GaN nanowall hexagonal honeycomb like network on c-plane sapphire under nitrogen rich (N/Ga ratio of 100) conditions at temperatures below 700 °C is demonstrated. The walls are c-oriented wurtzite structures 200 nm wide at base and taper to 10 nm at apex, manifesting electron confinement effects to tune optoelectronic properties. For substrate temperatures above 700 °C the nanowalls thicken to a flat morphology with a dislocation density of 10 10/cm2. The role of misfit dislocations in the GaN overlayer evolution is discussed in terms of growth kinetics being influenced by adatom diffusion, interactions and bonding at different temperatures. The GaN films are characterized by reflection high energy electron diffraction (RHEED), field emission scanning electron (FESEM), high resolution X-ray diffraction (HRXRD) and cathodoluminescence (CL).
|Original language||English (US)|
|Number of pages||3|
|Journal||Materials Research Bulletin|
|State||Published - Nov 2011|
Bibliographical noteFunding Information:
The authors thank Professor C.N.R. Rao for his constant encouragement and support. One of the authors Manoj Kesaria acknowledges Council of Scientific and Industrial Research, New Delhi, India for the Senior Research Fellowship.
- A. Nanostructures
- A. Nitride
- B. Epitaxial growth
- C. X-ray diffraction