Controlled Bipolar Doping of One-Dimensional van der Waals Nb₂Pd₃Se₈

Tailoring the electrical properties of one-dimensional (1D) van der Waals (vdW) materials is desirable for their applications toward electronic devices by exploiting their unique characteristics. However, 1D vdW materials have not been extensively investigated for modulation of their electrical properties. Here we control doping levels and types of 1D vdW Nb₂Pd₃Se₈ over a wide energy range by immersion in AuCl₃ or β-nicotinamide adenine dinucleotide (NADH) solutions, respectively. Through spectroscopic analyses and electrical characterizations, we confirm that the charges were effectively transferred to Nb₂Pd₃Se₈, and the dopant concentration was adjusted to the immersion time. Furthermore, we make the axial p-n junction of 1D Nb₂Pd₃Se₈ by a selective area p-doping using the AuCl₃ solution, which exhibits rectifying behavior with an I_forward/I_reverse of 81 and an ideality factor of 1.2. Our findings could pave the way to more practical and functional electronic devices based on 1D vdW materials.