Mid-Infrared ZnSe:Cr Diodes Based on Optically Enhanced Impact Ionization Process

摘要

Tunable mid-infrared light is an efficient tool for probing molecular structures and medium energy bondings in various materials. Cr{sup}(2+)-dopped ZnSe is widely used for diode-pumped laser operation in the 2-3μm wavelength range. Due to its electrical properties, this material is also identified as a good candidate for electrically pumped emission. We report mid-infrared electroluminescence observed at room-temperature from a bulk ZnSe:Cr single crystal. From a technological point of view, the ZnSe samples (typical dimensions 10 × 10 × 0.6 mm{sup}3) are Cr{sup}(2+)-doped up to concentrations of 10{sup}19cm{sup}(-3), and gold electrodes are evaporated on both faces (Fig. 1). The light emission is obtained in an avalanche regime (corresponding to an impact ionization process), with a first-run electro-optical conversion efficiency of ～10{sup}(-6) for an applied field of ～20kV.cm{sup}(-1) (Fig. 2a).