Temperature sensitivity of InGaAs quantum-dot lasers grown by MOCVD

Abstract

Temperature-dependent cavity length studies have been performed on multiple stack strain compensated InGaAs quantum-dot (QD) active region broad stripe laser structures grown by metal-organic chemical vapor deposition. The characteristic temperature coefficients of the threshold current density (T/sub 0/) and external differential quantum efficiency (T/sub 1/) were calculated from variable temperature measurements. The correlation of the T/sub 0/,T/sub 1/ values and the extracted values of the characteristic temperature coefficients of the transparency current density, material gain, injection efficiency, and internal loss (T/sub tr/,T/sub g0/,T/sub /spl eta/inj/,T/sub /spl alpha/i/) from the temperature-dependent study is discussed. The T/sub 1/ values are higher than 400 K for five-stack QD laser structures, comparable values to conventional quantum-well (QW) laser structures. T/sub 0/ values are lower than 100 K. Extracted material gain parameters are found to increase with increasing temperature for the three-stack QD structure, and are nearly temperature independent for the five-stack structure, different to that observed in InGaAs QW lasers.