Junction electroluminescence in CuInS2

We report the first observation of homojunction electroluminescence in CuInS2. These homojunctions are made by two different annealing procedures which convert a surface layer of p−type crystals. Diodes made by low−temperature (200 °C) In−Ga diffusion show a rectification ratio of 17000:1 at 2 V and a zero bias resistance of 1×107 Ω. For diodes made by high−temperature (600 °C) annealing in InCl3 the values are 15000:1 and 3×107 Ω, respectively. Electroluminescence has been observed in diodes made by In−Ga diffusion. The spectrum peaks at 1.48 eV at 300 °K and at 1.42 eV at 77 °K. The internal quantum efficiency is 10−5 at 300 °K and 10−3 at 77 °K.