Formation of manganese δ-doped atomic layer in wurtzite GaN

Abstract

We describe the formation of a δ-doped manganese layer embedded within c-plane wurtzite gallium nitride using a special molecular beam epitaxy growth process. Manganese is first deposited on the gallium-poor GaN (0001¯) surface, forming a 3×3−R30° reconstructed phase. This well-defined surface reconstruction is then nitrided using plasma nitridation, and gallium nitride is overgrown. The manganese content of the 3×3−R30° phase, namely one Mn per each 3×3−R30° unit cell, implies that the MnGaN alloy layer has a Mn concentration of up to 33%. The structure and chemical content of the surface are monitored beginning from the initial growth stage up through the overgrowth of 20 additional monolayers (MLs) of GaN. An exponential-like drop-off of the Mn signal with increasing GaN monolayers, as measured by Auger electron spectroscopy, indicates that the highly concentrated Mn layer remains at the δ-doped interface. A model of the resultant δ-doped structure is formulated based on the experimental data, and implications for possible spintronic applications are discussed.