Grain-size effect on pressure-induced semiconductor-to-metal transition in ZnS

The grain-size effect on the semiconductor-to-metal transition in ZnS has been investigated by in situ high-pressure electrical resistance and optical measurements. It is found that the grain-size effect can elevate the transition pressure of ZnS in a larger pressure range. On the basis of the results obtained and results reported in the literature, we demonstrate that the dangers of using the transition pressures of the II-VI compounds as pressure calibrators without a detailed knowledge of their grain-size effects on the transition pressures cannot be overstressed. (C) 1999 American Institute of Physics. [S0021-8979(99)03922-5].