Effect of p-doping profile on performance of strained multi-quantum-well InGaAsP-InP lasers

Leakage of electrons from the active region of InGaAsP-InP laser heterostructures with different profiles of acceptor doping was measured by a purely electrical technique together with the device threshold current. Comparison of the obtained results with modeling data and SIMS analysis shows that carrier leakage of electrons over the heterobarrier depends strongly on the profile of p-doping and level of injection. In the case of a structure with an undoped p-cladding/waveguide interface, the value of electron leakage current can reach 20% of the total pumping current at an injection current density of 10 kA/cm at 50/spl deg/C. It is shown that carrier leakage in InGaAsP-InP multi-quantum-well lasers can be minimized and the device performance improved by utilizing a p-doped separate-confinement-heterostructure layer.