Title :
Annealing amorphous GaN - a way to nano-crystalline state
Author :
Grigorescu, C.E.A. ; Lee, H.K. ; Lanke, U.D. ; Ruck, B.J. ; Monnereau, O. ; Notonier, R. ; Tonetto, A. ; Trodahl, H.J.
Author_Institution :
Nat. Inst. R&D Optoelectronics, Bucharest, Romania
fDate :
29 June-3 July 2003
Abstract :
The effects of thermal annealing on structural and optical properties of amorphous GaN thin films obtained by Ion Assisted Deposition (IAD) have been investigated. Thermal annealing. was carried out in flowing nitrogen and respectively under water vapour pressure (1.7-2.4 torr), at temperatures up to 800°C. From SEM observations of the annealing processes in real time it appears that formation of nano-crystallites in the amorphous environment occurs at about 400°C. XRD and Raman scattering performed on the annealed films prove the presence of nano-crystallites (2-4 nm). Optical measurements show a weak absorption edge in the as prepared film, and the deepening edge and reduced sub-band absorption after annealing.
Keywords :
III-V semiconductors; Raman spectra; X-ray diffraction; amorphous semiconductors; annealing; gallium compounds; nanostructured materials; scanning electron microscopy; semiconductor thin films; wide band gap semiconductors; 1.7 to 2.4 torr; 2 to 4 nm; 400 degC; 800 degC; GaN; Raman scattering; SEM; XRD; annealing amorphous GaN film; deepening edge; ion assisted deposition; nanocrystallites; optical properties; reduced sub-band absorption; structural properties; thermal annealing; weak absorption edge; Absorption; Amorphous materials; Annealing; Gallium nitride; Nitrogen; Optical films; Optical scattering; Particle beam optics; Sputtering; Temperature;
Conference_Titel :
Transparent Optical Networks, 2003. Proceedings of 2003 5th International Conference on
Print_ISBN :
0-7803-7816-4
DOI :
10.1109/ICTON.2003.1264649
