Non-alloyed Au/p-ZnSe/p-BeTe ohmic contact layers for ZnSe-based blue-green laser diodes

Non-alloyed Au/p-ZnSe/p-BeTe ohmic contact layers for ZnSe-based blue-green laser diodes with contact resistivity as low as 4.2 x 10(-4) Omega cm(2) are reported. This contact layer is basically dislocation free due to the low level of lattice misfit, as confirmed by TEM observations. The ZnSe layer serves as a contact layer and also as a protection layer for BeTe against oxidation. The electrical properties of tbc contact layers are strongly dependent on the ZnSe lever thickness. Au diffusion through the ZnSe layer down to the BeTe layer at room temperature is found to be responsible for the ohmic properties.