Electroluminescent devices based on junctions of indium doped zinc oxide and porous silicon

Electroluminescent devices (ELD) based on junctions of indium doped zinc oxide (ZnO:In) and porous silicon layers (PSL) are presented in this work. PSL with different thicknesses and photoluminescent emission, around 680 nm, were obtained by anodic etching. PSL were coated with a ZnO:In film which was obtained by ultrasonic spray pyrolysis technique. Once obtained, this structure was optically and electrically characterized. When the devices were electrically polarized they showed stable electroluminescence (EL) which was presented as dots scattered over the surface. These dots can be seen with the naked eye. The observed EL goes from the 410 to 1100 nm, which is formed by different emission bands. The EL emission in the visible region was around 400 to 750 nm, and the emission corresponding to the infrared part covers the 750 to 1150 nm. The electrical characterization was carried out by current-voltage curves (I-V) which show a rectifying behavior of the devices. Observed electroluminescent dots are associated with the electron-hole injection into quantized states in PS as well as the emission from the ZnO:In film.