Influence of Nd doping on electric properties of n-type SnO2 nanoparticles synthesized via sol–gel route

While rare-earth doping of SnO₂ has been widely explored for structural and optical tuning, experimental realization of stable p-type conduction remains challenging and insufficiently understood. Consequently, the present study reports the synthesis of pristine and Nd-doped SnO₂ nanoparticles [Sn_1-xNd_xO₂ NPs, where x = 0, 0.05, and 0.10] via a sol–gel route. X-ray diffraction coupled with Rietveld refinement confirms the formation of a single-phase tetragonal rutile structure with \(P{4}_{/2}mnm\) space group for all compositions, accompanied by a systematic reduction in crystallite size. Microstructural analysis reveals nanometric grains with decreased average size from 29 nm (x = 0) to 17 nm (x = 0.10), indicating dopant-induced suppression of grain growth. Electrical characterization shows ohmic I-V behavior with a marked reduction in resistance upon doping. Hall effect measurements provide direct evidence of a conduction-type transition from n-type to p-type, attributed to acceptor-type Nd³⁺ substitution at Sn⁴⁺ sites and associated defect compensation mechanisms. Dielectric studies further reveal enhanced permittivity and modified relaxation behavior consistent with Maxwell–Wagner interfacial polarization and Koop’s theory. Nd-doped p-type SnO₂ NPs with enhanced electrical and dielectric properties highlight the potential of these nanoparticles for optoelectronic devices, transparent conducting electrodes, and spintronic applications.