Shallow‐Donor‐Controlled Conduction in ZnMgO: Mg‐Induced Transition Between Variable‐Range and Nearest‐Neighbor Hopping Mechanisms

ZnMgO thin films (0%–3% Mg) were deposited via ultrasonic spray pyrolysis and characterized from 40 to 320 K. Three conduction regimes were identified: Mott variable‐range hopping (VRH), nearest‐neighbor hopping (NNH), and thermally activated conduction. At 0% Mg, VRH dominates; at 1–2% Mg, VRH and NNH coexist; and at 3% Mg, NNH prevails. Key parameters include a density of states near the Fermi level of 5.7 × 10 19 cm −3 eV −1 (0% Mg) and 3.9 × 10 18 cm −3 eV −1 (1% Mg), localization lengths of 11.0 nm (0% Mg) and 23.4 nm (1% Mg), hopping energies of 3.1 meV (VRH, 0% Mg) and 4.8 meV (VRH, 1% Mg), and NNH activation energies from 5.5 meV (1% Mg) to 9.9 meV (3% Mg). High‐temperature activation energy increases from 26.9 to 70.2 meV. Optical measurements show bandgap widening from 3.264 to 3.308 eV, aligning with transport trends. These results advance ZnMgO conduction understanding for optoelectronic and sensing applications.