Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Transformation of c-oriented nanowall network to a flat morphology in GaN films on c-plane sapphire
AU - Kesaria, Manoj
AU - Shetty, Satish
AU - Cohen, P.I.
AU - Shivaprasad, S. M.
PY - 2011/11
Y1 - 2011/11
N2 - 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 1010/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).
AB - 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 1010/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).
U2 - 10.1016/j.materresbull.2011.07.043
DO - 10.1016/j.materresbull.2011.07.043
M3 - Journal article
VL - 46
SP - 1811
EP - 1813
JO - Materials Research Bulletin
JF - Materials Research Bulletin
IS - 11
ER -