Temperature sensitivity of InGaAs quantum-dot lasers grown by MOCVD

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-0) and external differential quantum efficiency (T-1) were calculated from variable temperature measurements. The correlation of the T-0, T-1 values and the extracted values of the characteristic temperature coefficients of the transparency current density, material gain, injection efficiency, and internal loss (T-tr, T-g0, T-eta inj, T-alpha i) from the temperature-dependent study is discussed. The T-1 values are higher than 400 K for five-stack QD laser structures, comparable values to conventional quantum-well (QW) laser structures. T-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.