Optimized Band-Structure Design of Ingaasp Braqwet Structures

We developed InGaAsP BRAQWET (barrier, reservoir, and quantum-well electron transfer) structures using numerical modeling to optimize the band structure. The main improvement was achieved by including i,n,i,p-doped layers in the barrier, thus decoupling the quantum-well (QW) from the electric field in the barrier, The optimized structures show increased QW movement with applied bias, QW level close to the Fermi level at zero bias, low leakage current and low sensitivity to fabrication tolerances, such as layer thickness and doping levels. The new structures should show improved performance and be easier to manufacture due to their higher tolerances. BRAQWET structures were grown according to the new design by CBE and show low leakage current (10mA/cm(2)) and typical band-filling effects at lambda=1.51 mu m, making them potentially suitable for high-performance modulators.