In recent years there has been considerable interest in blue EL emitted by forward-biased ZnSe MIS diodes

[1-5]

. In our earlier work

[6

7]

attention was directed to determining the origin of two emission bands in the blue at 4655 and 4770 Å at room temperature. In the present paper the main interest is focused on the spatial distribution of blue EL in ZnSe MIS diodes.Nominally undoped ZnSe crystal

grown in this laboratory

were used in the present experiments. The boule crystals were grown from the vapour phase in sealed capsules containing slight excess of zinc

[8

9]

. Dice with dimensions of 3×3×1 mm

3

were cut from the boules

and annealed in molten zinc at 850℃ for 100 h to reduce their resistivities to the range 1-10Ωcm. After polishing and etching

one large area face of the dice was then provided with an indium ohmic contact. A thick (500-1000 Å) layer of ZnS was deposited on the opposite face by electron beam

and finally a circular gold electrode 1 mm in diameter was evaporated on top of ZnS layer.The photo of EL spots was taken from the surface of the dice carrying the gold contact with Model XJL-01 optical microscope. Model HHS-2X scanning electron microscope has been used to study the ZnSe diodes.