We have first succeeded in fabricating intrinsic pn-junctions and in realizing pure green ZnTe light-emitting diodes (LEDs). This success has been achieved by the growth of high-quality ZnTe single crystals with low defect densities and by the realization of n-type layers in the p-type ZnTe substrates by a thermal diffusion process. EBIC observation and I-V measurement confirmed the formation of the intrinsic pn-junction. Electroluminesence at 550 nm is visualized under room light at room temperature.