Growth of the Zn1−xMnxO alloy by the MOCVD technique

Single-phase thin films of the diluted magnetic semiconductor Zn1−xMnxO have been grown by the MOCVD technique. Depositions have been done at T = 450 °C on fused silica and (0 0 0 1) sapphire substrates. Layers on silica exhibit polycrystalline structure with [0 0 1] preferential orientation while Zn1−xMnxO films are (0 0 0 1) epitaxially grown on c-sapphire with the epitaxy relation: 30° rotation of the Zn1−xMnxO [1 0 0] direction with respect to the [1 0 0] of the substrate. The manganese content varies in the (0-30%) range and is always higher in samples grown on sapphire substrates under the same conditions. Variations of a and c lattice parameters, assessed by X-ray diffraction, follow Vegard's law and attest to the incorporation of substitutional Mn2+ ions. Hall effect measurements show a decrease of the mobility with the incorporation of manganese in ZnO, and optical transmission results present the shift of the absorption edge towards higher energies.