title: Optical properties of ultra-thin (< 30 nm) GaN layers on c-sapphire substrates with different initial growth conditions measured by surface-plasmon enhanced Raman scattering.
abstract: We have carried out surface-plasmon enhanced Raman spectroscopy (SERS) on 30 nm-thick GaN samples grown at various temperatures, in order to investigate the properties of ultra thin GaN films on sapphire. We found that the properties, such as the strain and the free-carrier density of the thin layers, were sensitively affected by the growth temperatures. Our results show that SERS, by selectively enhancing the Raman signal near the surface, can be a very useful technique to investigate the optical properties of ultra-thin GaN films and their initial growth mode.
authors.forename: Ho-Jong
authors.initials: HJ
authors.lastname: Kim
authors.forename: Tae-Soo
authors.initials: TS
authors.lastname: Kim
authors.forename: Jin-Gyu
authors.initials: JG
authors.lastname: Lee
authors.forename: Jung Hoon
authors.initials: JH
authors.lastname: Song