PHOTOELECTRONIC PROPERTIES OF SYNTHETIC MERCURY SULPHIDE CRYSTALS

Experimental studies have been made of the photoelectronic properties of mercury sulphide crystals grown in an argon atmosphere by a slow convection technique. Peak photoconductivity for HgS (ρ{variant} ∼1012 Ω cm) occurred at ∼6000 Å at room temperature; the temperature coefficient of the edge being -9 × 10-4 eV/deg. Emphasis is placed on the techniques of space charge conduction and quenching of photoconductivity which have been used to determine the location of localized levels in the energy gap. Results indicate that some degree of compensation is present in HgS. Combined measurements of thermally activated ohmic and space charge limited conduction yield dominant electron and hole levels 0.62 and 1.08 eV, respectively, from the conduction band while the two band quenching spectra (characteristic of other II-VI semiconductors) show thresholds for optical quenching at 0.67 and l.08eV. Some results are also presented for crystals grown in the absence of any gas at 300°C but doped with the elements Ag, In and Cu. © 1969.