X-ray Absorption and Emission Studies of Mn-doped ZnO Thin Films

Abstract

The electronic structure of Mn-doped ZnO thin films, a dilute magnetic semiconductor (DMS) having possible room temperature (RT) ferromagnetism, synthesized with nominal compositions of Zn1 xMnxO (x = 0.03, 0.05, 0.07, 0.10, and 0.15) by using the spray pyrolysis method are investigated using soft X-ray absorption and emission spectroscopy. The intensity of the pre-edge spectral feature at the O K-edge increases with Mn concentration, which clearly reveals that there is a strong hybridization of Mn ions with the ZnO matrix. The near-edge X-ray absorption fine structure (NEXAFS) measurements at the Mn K- and L3,2-edges show a mixed valence nature for the Mn ions, with Mn 2+ and Mn 3+ /Mn 4+ states, and the Mn 3+ /Mn 4+ states are observed to increase with the Mn-concentration. Mn L2,3 resonant inelastic X-ray scattering (RIXS) measurements show that the excess Mn interstitials appear in the sample and that direct exchange interactions with substitutional Mn atoms may explain the magnetic interaction in Mn-doped ZnO.