High-purity single crystals of ZnS

x

Se

1-x

(

x

=0.15) were grown with sublimation method under a controlled partial pressure of selenium and sulphur corresponding to the minimum total pressure. The crystal wafers were taken from the grown ZnS

x

Se

1-x

single crystal on cleaving along the (110) cleavage plane. The cleaved crystals were heat-treated at 1024℃ for 64 hours in molten Zn

which is labelled sample A. The sample A was heat-treated again at 350℃ for 3 hours

this sample is labelled B. When the sample A was heat-treated at 1030℃ for 119 hours under 100 Torr of the zinc partial pressure

it is labelled C. Ohmic contacts of In dot were made with a supersonic soldering iron. The carrier concentration and Hall mobility of n-ZnS

x

Se

1-x

(

x

=0.15) were measured at the range of from liquid nitrogen temperature to room temperature with Van der Pauw method.