<p>In this paper, Zn₂MnO₄ and Fe-doped Zn₂MnO₄ thin films were prepared by economical spray pyrolysis at 260&#xa0;°C. X-ray diffraction confirms a polycrystalline tetragonal phase across all compositions, with increasing Fe-content leading to crystallite refinement, higher lattice strain, and a higher dislocation density. Optical measurements show a direct allowed transition, with a systematic decrease in the bandgap from 2.97&#xa0;eV (undoped) to 2.59&#xa0;eV (8.5 wt % Fe), accompanied by a larger Urbach energy and a higher refractive index. Dispersion studies have shown that the increase in iron ratio enhances the static refractive index (n_o) from 1.77 to 2.25, dispersion energy (<i>E</i>_d) from 11.74 to 15.26&#xa0;eV, and the static dielectric constant (<InlineEquation ID="IEq1"> <EquationSource Format="TEX">\({\varepsilon}_{s}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>ε</mi> <mi>s</mi> </msub> </math></EquationSource> </InlineEquation>) from 3.41 to 4.98. Optoelectrical analyses indicate a higher optical carrier contribution, a larger plasma frequency and optical conductivity, and a higher relaxation time with increasing Fe-doping concentration. Nonlinear-optical parameters (<InlineEquation ID="IEq2"> <EquationSource Format="TEX">\({\chi }^{(1)}\)</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mrow> <mi>χ</mi> </mrow> <mrow> <mo stretchy="false">(</mo> <mn>1</mn> <mo stretchy="false">)</mo> </mrow> </msup> </math></EquationSource> </InlineEquation>, <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\({\chi }^{(3)}\)</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mrow> <mi>χ</mi> </mrow> <mrow> <mo stretchy="false">(</mo> <mn>3</mn> <mo stretchy="false">)</mo> </mrow> </msup> </math></EquationSource> </InlineEquation>, <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\({n}_{2}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>n</mi> <mn>2</mn> </msub> </math></EquationSource> </InlineEquation>) were estimated via Miller’s relations and show an improvement with increasing the Fe-dopant concentration. Hot-probe tests identify n-type conductivity for all Zn₂MnO₄ and Fe-doped Zn₂MnO₄ thin films. The electrical study reveals that the Al/p-Si/Fe: Zn₂MnO₄/Al heterojunction exhibits improved diode quality with increasing Fe concentration. The ideality factor decreases from 1.52 to 1.43, the barrier height of the Al/p-Si/Fe: Zn₂MnO₄/Al heterojunction increases from 0.81 to 0.89&#xa0;eV, and the rectification ratio at symmetric bias improves with increasing Fe content.</p>