Study on electrical properties of II-VI-based distributed Bragg reflectors

The key technology for electrically pumped vertical-cavity surface-emitting lasers (VCSEL) is the realisation of high reflectivity Bragg Mirrors (DBRs) with sufficient conductivity in vertical direction. Several nand p-doped DBRs, consisting of ZnSSe as high index and a MgS/Zn(Cd)Se superlattice (SL) as low index material were grown on GaAs substrates. Mesa structures were prepared and furnished with metal contacts. On the one hand a sufficient conductivity of n-doped DBRs has been achieved. The conductivity depends strongly on the period and composition of the MgS/Zn(Cd)Se-SL. On the other hand the p-doped DBRs showed a resistance of several orders of magnitude higher and are unlikely to be used in VCSELs. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)