Characterization and modeling of InGaAs/GaAs multiple quantum well lasers by capacitance-voltage measurements

摘要

Abstract: We have measured and analyzed the room-temperaturecapacitance-voltage (C-V) characteristics ofIn$-0.35$/Ga$- 0.65$/As/GaAs MQW laser structures withdifferent doping levels in the active region. Averagedoping densities in the well-barrier regions weredirectly extracted from the as- measured carrierprofiles. A model for he C-V measurement, including theself-consistent solution of Poisson and Schroedingerequations, was developed. The carrier profiles obtainedfrom the simulated C-V characteristics do notcorrespond to the free carrier profiles since the localcharge neutrality hypothesis does not hold for QWstructures. Thus, the true carrier distribution canonly be determined from a full quantum-mechanicalsimulation of the laser structure. We have determined,form the comparison between experimental and simulatedprofiles, a conduction band offset$Delta@E$-c$//$Delta@E$-g$/ of 0.81. We have alsoapplied C-V measurements to samples with interdiffusedQWs, and obtained the characteristic interdiffusionlength. !19