Abstract:

The reflected spectra of GaN-based DBR for blue LED are studied by transfer matrix method. The results show that reflective spectra of S-polarized and P-polarized plane waves are the same at normal incidence, but both of them move to high frequency and the difference between the two grow rapidly with increasing angle of incidence. Change rate of DBR reflected spectra with increasing the angle related to incident medium, and low refractive index of incident medium has a broader incident response. To calculate many times by modifying the structural parameters found that correcting the thickness of films by the angle of incidence for increasing wide-angle reflection is a good method. Coupled DBR increasing wide-angle reflection at the cost of reduce reflectivity or doubled the thickness of films. Reflected spectra of coupled DBR design is better than that of the conventional DBR design, which is important to enhance light extraction efficiency from LED.

Key words: optoelectronics, GaN, transfer matrix, distributed Bragg reflector, incident angle