An analytical model of a new device called junctionless accumulation-mode triple-material surrounding gate (JATMSG) nanowire transistors is presented for the very first time using a different approach. The doping concentration and the charge concentrations are taken into consideration, and the method is a quite easy approach of Poisson equation and its solution using Fourier–Bessel function method. The device performance is investigated through the analysis of the parameters central potential and electric field for various parameters, and the results are simulated using TCAD tool. The results align well with the software simulation results. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2026.