Fig. 8. Electrical characteristics of the Sn series: (A) current–voltage characteristics of the Sn series, (B) log(I) vs. V^0.5 plots for the S10 sample at different step scans, (C) current–voltage characteristics of the S10 sample at different step scans, and (D) electrical resistance for the Sn samples and an individual S10 sample at different step scans.