Effect of barrier layer width on the optical and spectral properties of InAsP/AlGaInP quantum dot lasers.

The barrier layer thickness separating the dot-in-well structure in optoelectronic devices plays a crucial impact on the performance of these devices. Here, we report the effect of the barrier width in quantum dot (QD) laser. Three series of InAsP QD lasers were papered with different barrier widths (i.e., 8, 16, and 24 nm) of (AlGa)InP. The samples were prepared by MOVPE at 730 °C. Data of threshold current density, J th giving a lower J th for 8 nm barrier width sample and it becomes more temperature dependency evident by a low value of characteristic temperature, T o ≈ 77 k. Emission spectra of 2 mm long lasers showed a blue-shift by approximately 11 nm when the barrier width increased from 8 to 24 nm. The modal absorption study showed a decrease in the inhomogeneous broadening for 24 nm barrier width sample. Simulation results revealed an increase in the optical absorption cross-section, σ o with increasing barrier width. These results showed that significant improvements in the spectral properties of the InAsP QD lasers can be made by altering the (AlGa)InP barrier width. • The effect of the barrier width of (AlGa)InP quantum wells (i.e., 8, 16, and 24 nm) on the operation of InAsP QD lasers was investigated. • 8-nm barrier width sample revealed lower threshold current density. • Lasing emission showed an 11 nm blue-shift when the barrier width varied from 8 to 24 nm. • The inhomogeneous broadening of the ground state and exited states decreases at 24-nm barrier width sample. • Simulation results raveled increase of the optical absorption cross-section σ o , with increasing barrier width. • Significant improvements on the optical and spectral properties of the InAsP QD lasers can be made by altering the (AlGa)InP barrier width. [ABSTRACT FROM AUTHOR]