Full text loading...
(a) SEM image of an array of GaN core-shell LEDs with nominal pattern opening diameter of about 1 μm and pitch of about 5.9 μm, respectively. The sample was tilted to 30° for a better view. (b) TEM cross-section image of an individual core-shell GaN rod. Inset: enlarged view of the 3× InGaN/GaN MQWs grown on the sidewall. (c) An enlarged view of the top corner of the core-shell GaN LED to show the detail of MQWs and p-GaN layer structure. (d) An enlarged view of the bottom corner of the core-shell GaN LED.
Spatially and spectrally resolved cathodoluminescence measurements. (a) A CL spectrum of an ensemble of GaN core-shell LEDs excited on sidewalls of the rods. Inset: an SEM image superimposed by a monochromatic CL image detected at a fixed wavelength of 418 nm. (b) A CL spectrum of an ensemble of GaN core-shell LEDs excited from the top surface of the rods. Insets: two SEM images superimposed by monochromatic CL images detected at fixed wavelength of 412 nm and 460 nm. (c) A set of CL spectra taken from a TEM ready GaN core-shell LED sample along a line ranging from the sidewall surface to the center of the rod. Insets: left: SEM image of the cleaved surface and indication of the CL scanning line; right: the schematics of the core-shell LED and CL scanning line.
Internal quantum efficiency measurement by power and temperature dependent photoluminescence with a 380 nm Ar-ion laser. (a) IQE versus laser power at different temperature. (b) IQE versus temperature at 27 mW laser power.
Article metrics loading...