Electrical Property and Phase Transition of CdSe under High Pressure

The electrical resistivity of powdered CdSe has been measured at 300～450 K and pressure up to 23 GPa using fabricating microcircuit on a diamond anvil. It is found that during loading the pressure dependence of the electrical resistivity shows anomaly at about 2.6 GPa, corresponding to the structure transition of CdSe from wurtzite to rock-salt structure. While the anomalies observed at 6.0 GPa, 9.8 GPa and 17.0 GPa are due to the electronic structure transitions. During unloading two extra anomalies can be detected which happen at 14.0 GPa and 3.0 GPa, respectively. By fitting to the curve of pressure dependence of electrical resistivity the pressure dependence of band gap of CdSe high pressure phase has been obtained. The pressure of metallization of CdSe can be predicted to happen in the pressure range of 70～100 GPa. The elevated experiment results indicate that the electrical resistivity of CdSe increases with increasing temperature in the measured pressure and temperature range.