X-ray diffraction study of the AgCd2−xMnxGaS4 semiconductor alloys and their electrical, optical, and photoelectrical properties

Abstract The AgCd 2− x Mn x GaS 4 alloys were investigated by powder X-ray diffraction. The AgCd 2− x Mn x GaS 4 solid solutions exist in the range of 0 ⩽ x ⩽ 1.2 4 . The refinement of the AgCd 0.8 Mn 1.2 GaS 4 crystal structure (Pmn2 1 space group, a = 0.8 0 7 6 8 ( 3 ) nm , b = 0.6 8 1 0 5 ( 2 ) nm , c = 0.6 5 2 0 3 ( 2 ) nm , V = 0.3 5 8 6 6 ( 4 ) nm 3 ) has proved the isovalent substitution of Cd with Mn. The band gap energy of the solid solutions has been estimated from the intrinsic absorption edge at 300 K. Within the solid solutions range, the band gap increases from 2.15 eV for the AgCd 2 GaS 4 composition to 2.4 eV for the AgCd 0.8 Mn 1.2 GaS 4 composition. The spectral distribution of photoconductivity has been investigated for different compositions. The AgCd 2− x Mn x GaS 4 alloys with x ⩽0.30 exhibit the highest photosensitivity. The strong photoconductivity in the 600–610 nm region is attributed to the presence of cadmium vacancies or cadmium-containing complexes in the crystal structure, which act as the photoactive centers.