ZnTe-Based Light-Emitting Diodes Fabricated by Solid-State Diffusion of Al through Al Oxide Layer

The solid-state diffusion of Al in ZnTe through an Al oxide layer was examined for the fabrication of ZnTe-based light-emitting diodes (LEDs). By chancing the thickness of the Al oxide layer deposited on a clean ZnTe surface, the Al concentration at the surface of ZnTe can be adjusted. The excellent uniformity of the diffusion depth of Al was obtained by using the Al oxide layer, in contrast to the previous oxide layer prepared by O radical irradiation. Current-voltage (I-V) characteristics and the output power of ZnTe LED can be controlled by the thickness of the Al oxide layer. The maximum output power obtained was as high as 18 mu W under a forward current density of 8 A/cm(2) in spite of a strong self-absorption effect. Therefore, the Al oxide layer can be used as a good diffusion-limiting layer for fabricating ZnTe LEDs by thermal diffusion. (C) 2009 The Japan Society of Applied Physics