OPTICAL-PUMPED LASING OF DOPED ZNSE EPILAYERS GROWN BY MOVPE

Laser action in undoped, nitrogen and chlorine doped ZnSe epitaxial la yers has been investigated for pulsed optical excitation with a 1kHz r epetition rate by N-2 laser radiation from liquid-nitrogen temperature s up to near room temperature. The highest value of the laser energy a nd power output of ZnSe lasers were E = 5 x 10(-8) J and P = 5 CV at I -exc = 800 kW/cm(2). The laser line positions are between lambda = 449 and 456 nm. II was shown that doping of ZnSe with both acceptor or do nor impurities as well as using a ZnMgSSe barrier layer between the Zn Se active layer and the substrate is favourable to increase the PL eff iciency and to decrease the laser threshold. The lowest threshold valu e (130-150 kW/cm(2)) was achieved in ZnSe:N grown with hydrogen carrie r gas. The results obtained from the measurements of the laser line po sitions as well as from the evaluation of the nonequilibrium carrier c oncentration proves that the ZnSe lasing mechanism under the excitatio n of the N-2 laser radiation is the recombination in an electron-hole plasma.