ZnSe has the potential to be used to make blue LED because it has wide band gap

and its strong blue exciton luminescence is observed even at the room temperature

[1]

. The main obstruction in practice is that the p-type ZnSe with low resistivity is difficult to produce due to self-compensation. It seems that the self-compensation effect is related to the native defects originating in nonstoich-iometry during crystal growth

[1]

. The two electron traps which are located at 0.30 and 0.33eV (labeled as A and B thereafter) below conduction band are commonly observed in ZnSe. Some authors suggested that these traps be associated with Se vacancies

[3

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.