Electrical and Optical Properties of GaSe

Absorption, photoconductivity, resistivity, and Hall coefficient of GaSe are measured. The photoconductivity spectrum reflects the exciton absortion. The crystal is p -type with two activation energies, of which value is about 0.26 eV above 200°K and 0.12 eV below 200°K for one specimen. Temperature dependence of the mobility is given by µ∝ T - n , where n is about 2. Ratio of the resistivity perpendicular to the layers to parallel one is about 10∼50. The activation energy almost equal for both orientations. Electric field dependence of the conductivity perpendicular to the layers is explained by an “anomalous” Poole-Frenkel effect. Estimated dielectric constant is ε =5.7 at 293°K and 6.6 at 102°K.