Investigation of electrical transport properties in solution-processed Bi₂Se₃-AgMnOOH nanocomposite

In this paper, we report the fundamental electrical transport properties measured in Bi₂Se₃-AgMnOOH nanocomposite disc, which is prepared for the first time by convenient low temperature solution-phase chemistry in conjunction with redox-mediated methodology. The comparative structural and morphological analyses for the nanocomposite with pristine Bi₂Se₃ are comprehensively investigated by different material characterization techniques. The results demonstrate the successful in situ composite fabrication between the Bi₂Se₃, Ag and γ-MnOOH components. Besides, the present work introduces a systematic approach for the examination of electrical transport properties in Ohmic and non-Ohmic regimes over a wide temperature range. The results from the room temperature transport measurement exhibited that the nanocomposite demonstrated non-linearity after a certain current I₀ (onset current), whereas Bi₂Se₃ was linear in the entire measured current range. An enhancement of the conductance was observed for Bi₂Se₃-AgMnOOH compared to the pure Bi₂Se₃ material, which is credited to the composite effect. The onset exponents x_T (DC conductance) and x_f (AC conductance) with phase-sensitive character demonstrate different values below and above 180 K separating two different phases with different conduction mechanisms. Also, flicker noise analysis established the correlation between the DC conductance in terms of Ohmic to non-Ohmic transition after the onset voltage V₀. This transition phenomenon from Ohmic to non-Ohmic behaviour is explained from the structural point of view of the nanocomposite. The present investigation highlights the importance of using the bottom-up solution-phase strategy for the synthesis of high quality Bi₂Se₃-based nanocomposites for transport studies and their possible future applications.