2024/12/09 by Youcheng Zhang, Stefano Pecorario, Zhang, Youcheng +17
Engineering · Materials Science · #Applied Physics (physics.app-ph) #Chalcogenide Semiconductor Thin Films #FOS: Physical sciences #Perovskite Materials and Applications #ZnO doping and properties
paper · pdf · doi:10.48550/arxiv.2412.06591
openalex publication_date 2024/12/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Recent reports highlight the potential of tin-based perovskite semiconductors for high-performance p-type field-effect transistors (FETs) with mobilities exceeding 20 cm2V-1s-1. However, these high mobilities--often obtained via two-probe (2P) methods on devices with small channel length-to-width ratios (L/W < 0.5) operating in the saturation regime at high drain-source currents--raise concerns about overestimation due to contact resistance and non-ideal FET characteristics. Here, we performed gated four-point probe (4PP) FET measurements on Hall bar devices (L/W = 6) of Cs0.15FA0.85SnI3, obtaining a consistent mobility of 3.3 cm2V-1s-1. Upon comparing these with gated 2P measurements of narrow-channel FETs (L/W = 0.1) on the same chip, we resolved the contact resistance (RC). The 2P linear mobility is underestimated due to voltage drops across RC, while the 2P saturation mobility is overestimated because of high (dRC)/(dVG) near the threshold. Contact resistance effects become more pronounced at lower temperatures. Contact-corrected four-point-probe (4PP) mobilities are independent of bias conditions and are observed to flatten at temperatures lower than 180 K. Future reports of perovskite FET mobilities should include gated 4PP measurements and use devices with larger L/W ratios to minimize nonidealities arising from contact resistance effects.