Activation of N-Acceptor in MOCVD-ZnSe by Excimer Laser Annealing

The recent success in obtaining blue-green diode lasers using ZnSe-based heterostructures has been mainly due to the successful p-doping of ZnSe using a N plasma source in an MBE system. P-type ZnSe can also be grown by MOCVD, using NH 3 as the dopant source. Dopant concentrations of up to 10 18 cm −3 have been obtained but net acceptor concentrations are in the range of only about 10 15 cm −3 Activation of the remaining N has been achieved to some extent (N A -N D ∼3*10 16 cm −3 ) by rapid thermal annealing. However, this has had limited success. We have used fast surface annealing by an excimer laser to activate the N. We have observed an increase in the ratio of Acceptor Bound Exciton peak intensity to Free Exciton peak intensity on annealing and this effect increases as we increase the laser power density from 10 to 30 MW/cm 2 . Electrical measurements ( C-V ) give a net acceptor concentration of ∼2*10 16 cm −3 and thus confirm the increase in carrier concentration after annealing.