<Original Paper>Discussion on the Annealing Method for ZnSe : N/ZnSe

Metalorganic chemical vapor deposition (MOCVD) is an important growth method for preparing p-type ZnSe epilayer as the large area growth can be performed. However, it is still very difficult for this method to obtain the enough high acceptor concentration that can satisfy the demand for fabricating a light-emitting device. This is due to hydrogen passivation (nitrogen atoms form N-H complexes with hydrogen atoms). In order to enhance active concentration of nitrogen in a ZnSe epilayer, the bonds connected with nitrogen atoms must be broken. In this experiment, ZnSe epilayers doped with nitrogen (N) has been grown on ZnSe substrates at the lower temperature by a low-pressure MOCVD system using hydrogen as a carrier gas and ammonia as a dopant source. Then, ZnSe : N/ZnSe was annealed in molten Zinc and zinc-saturated vapor pressure. Photoluminescence (PL) spectra measured at 4.2K showed stronger I_1^N emission from ZnSe : N epilayers annealed at optimized conditions. The ionization energy of nitrogen acceptor in ZnSe epilayer is estimated to be 109meV by examining the dependence of DAP emission on measuring temperature. Furthermore, C-V measurement revealed that ZnSe : Nepitaxial layer is p-type conduction and the highest net acceptor concentration reaches to high as 6.6×10^cm^. This is the highest value obtained so far for ZnSe homosystem epilayers grown by the MOCVD