Title :
Omnidirectional reflective contacts for light-emitting diodes
Author :
Gessmann, T. ; Schubert, E.F. ; Graff, J.W. ; Streubel, K. ; Karnutsch, C.
Author_Institution :
Dept. of Electr., Rensselaer Polytech. Inst., Troy, NY, USA
Abstract :
An electrically conductive omnidirectional reflector (ODR) is demonstrated in an AlGaInP light-emitting diode (LED). The ODR serves as p-type contact and comprises the semiconductor, a metal layer and an intermediate low-refractive index dielectric layer. The dielectric layer is perforated by an array of AuZn microcontacts thus enabling electrical conductivity. It is shown that the ODR significantly increases light extraction from an AlGaInP LED as compared to a reference LED employing a distributed Bragg reflector (DBR). External quantum efficiencies of 18% and 11% are obtained for the ODR- and the DBR-LED, respectively.
Keywords :
III-V semiconductors; aluminium compounds; electrical conductivity; gallium compounds; indium compounds; light emitting diodes; mirrors; ohmic contacts; reflectivity; 11 percent; 18 percent; AlGaInP; AlGaInP light-emitting diode; AuZn; AuZn microcontact array; LED; electrical conductivity; electrically conductive omnidirectional reflector; external quantum efficiencies; intermediate low-refractive index dielectric layer; light extraction; omnidirectional reflective contacts; p-type ohmic contact; reflectivity; Conductivity; Contacts; Dielectrics; Distributed Bragg reflectors; Gallium arsenide; Light emitting diodes; Optical reflection; Reflectivity; Semiconductor materials; Substrates;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2003.817386
