Title :
Thermal conductivity reduction in GaAs-AlAs distributed Bragg reflectors
Author :
Piprek, J. ; Troger, T. ; Schroter, B. ; Kolodzey, J. ; Ih, C.S.
Author_Institution :
Delaware Univ., Newark, DE, USA
Abstract :
Self-heating of vertical-cavity laser diodes is strongly affected by the thermal conductivity of the distributed Bragg reflectors (DBRs). Binary GaAs-AlAs DBRs are expected to be good heat conductors, but investigations of GaAs-AlAs superlattices indicate strong interface scattering of phonons. For the first time, we present direct thermal conductivity measurements of separated GaAs-AlAs DBRs with a quarter-wave layer thickness of more than 100 nm (tuned to 1.55-μm wavelength). Using an ac calorimetric method and finite element analysis, we measure about 50% thermal conductivity reduction compared to the average bulk value. GaAs-AlAs DBR´s for shorter wavelengths are expected to show an even lower thermal conductivity.
Keywords :
III-V semiconductors; aluminium compounds; calorimetry; distributed Bragg reflector lasers; finite element analysis; gallium arsenide; laser cavity resonators; laser transitions; laser tuning; semiconductor lasers; semiconductor superlattices; surface emitting lasers; thermal conductivity; 1.55 mum; DBR; GaAs-AlAs; GaAs-AlAs DBR laser diodes; GaAs-AlAs distributed Bragg reflectors; GaAs-AlAs superlattices; ac calorimetric method; average bulk value; direct thermal conductivity measurements; finite element analysis; good heat conductors; lower thermal conductivity; quarter-wave layer thickness; self-heating; strong phonon interface scattering; thermal conductivity reduction; vertical-cavity laser diodes; Conductivity measurement; Conductors; Diode lasers; Distributed Bragg reflectors; Finite element methods; Phonons; Scattering; Superlattices; Thermal conductivity; Wavelength measurement;
Journal_Title :
Photonics Technology Letters, IEEE
