Abstract: A method for purifying an n-type ZnO and/or ZnMgO substrate to reduce or eliminate the residual extrinsic impurities including introducing a reactive species having strong chemical affinity for at least one of the residual extrinsic impurities, and/or being capable of creating crystalline defects, is introduced in at least one region of the substrate, the reactive species being P, and whereby at least one getter region capable of trapping the said residual extrinsic impurities and/or in which the residual extrinsic impurities are trapped is created in the substrate; then annealing the substrate to cause diffusion of the residual extrinsic impurities towards the getter region and/or to outside the getter region. A method for preparing a p-doped ZnO and/or ZnMgO substrate comprising purifying an n-type ZnO and/or ZnMgO substrate using the above purification method in which one or more reactive species are used not limited to phosphorus alone.

Abstract: A method for purifying an n-type ZnO and/or ZnMgO substrate to reduce or eliminate the residual extrinsic impurities of the substrate with a view to p-doping of at least are part of the substrate, wherein a reactive species having strong chemical affinity for at least one of the residual extrinsic impurities, and/or being capable of creating crystalline defects, is introduced in at least one region of the substrate, the said reactive species being P, and whereby at least one region called a getter region capable of trapping the said residual extrinsic impurities and/or in which the residual extrinsic impurities are trapped is created in the substrate; annealing of the substrate is then carried out to cause diffusion of the residual extrinsic impurities towards the getter region and/or to outside the getter region, preferably towards at least one surface of the substrate.