Optical characteristics of InGaN/GaN light-emitting diodes depending on wafer bowing controlled by laser-treated grid patterns.
Opt Express
; 24(21): 24153-24160, 2016 Oct 17.
Article
in En
| MEDLINE
| ID: mdl-27828246
ABSTRACT
We evaluated the effects of grid patterns (GPs) realized on 2-inch sapphire substrates by simple laser treatment on the device characteristics of InGaN/GaN light-emitting diodes (LEDs). The degrees of wafer bowing for the LEDs with distances between the GPs of 1 (GP1-LED), 2 (GP2-LED), and 3 mm (GP3-LED) were 100.05, 100.43, and 101.59 µm, respectively, which are significantly improved compared to that (108.06 µm) of a conventional LED (C-LED) without GPs. Consequently, a blue-shift of the emission wavelength for the GP-LEDs was observed compared to the C-LED via alleviation of the quantum-confined stark effect. A comparative study of the fluorescence microscopy images of the C-LED and GP2-LED samples showed a significant reduction of threading dislocations as a result of the GPs. In the electroluminescence mapping results for the entire 2-inch region, the standard deviations of the emission wavelengths were 1.64, 1.49, and 2.55 nm for the GP1-LED, GP2-LED, and GP3-LED samples, respectively, which are smaller than that of the C-LED (2.66 nm). In addition, the average output power of the GP2-LED was 8.5% higher than that of the C-LED.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Opt Express
Journal subject:
OFTALMOLOGIA
Year:
2016
Type:
Article