超平坦井戸の発光像とスペクトル By Dr. Ji-Won Oh 25 20 15 10 5 30

Atomic Force Microscope Image of Atomic Steps on Atomically flat (110) GaAs QW

Ti-Sa PL 6.8 mm GaAs AlGaAs Ti-Sa Ext.(730nm) with uniform excitation Atomically Flat mm 6nm 6.8 mm GaAs 29% AlGaAs AlGaAs mm

PL image & spectra (4K) Energy transfer dynamics among islands : Any dependence on temp and density of steps in ldiff? mm

PL image & spectra (4K) mm

Longer diffusion length At 30K t=4000 ps m=4000 By Hilmer et. al. Phys. Rev. B.42. 3220-3223 (1990) in our data Longer diffusion length

PL Mission to Investigate Point excitation of Surface Steps : FWHM of PL spectra from Individual Islands and pits: Any dependence on size and steps ? 6.8 mm

・Spatially Uniform point excitation beam shape : accomplished with spatial filter But,… ・Optimization of microscopic PL experiments: Still not resolve n+2~3 spectra and thick spectra compared to previous experiments: need to find out excitation intensity which is weak enough not to cause negative factors in PL measurements and analysis and sharp cut filter system passing spectra between 750 nm ~ 800 nm only.