Effect of Electric Field on Photoconductivity of р-GaSe Single Crystals

Under various external and intracrystalline conditions (various temperatures, electric field strengths, initial values of the dark resistivity of the sample, the content and chemical nature of the introduced rare-earth impurity), the effect of a galvanically applied electric field on the intrinsic photoconductivity in single crystals of gallium selenide (p-GaSe) is studied. It is found that the photoconductivity in the samples of undoped p-GaSe single crystals with the initial dark resistivity ρ_D0 ≤ 4·10⁴ Ω·cm at T = 77 K, as well as in the samples doped with rare earth elements (dysprosium and erbium) with a content of N_REE ≥10^–2 at.% does not depend on the electric field strength. In the samples of undoped single crystals with ρ_D0 > 10⁵ Ω·cm and in the doped ones with N_REE < 10^–2 at.%, the photoconductivity depends on the electric field strength at Т ≤ 250 K and low illumination. The observed effect of the electric field on the photoconductivity in the studied samples of p-GaSe single crystals is explained by the electric rectification of electron potential fluctuation of empty energy bands caused by the presence of random macroscopic defects in the crystals.