This paper includes the effect of barrier length variations associated with the I–V characteristics of GaAs/AlGaAs Resonant Tunneling Diode (RTD). The changes in device like electron density, charge density and Fermi levels have been shown with their characteristics, which give the actual behavior of the device and helps in analyzing the device. Furthermore, comparison of these changes with previous have also been calculated and simulated with the help of simulation tool. Simulation performed using Nextnano3 and Atlas tools which confirm the various characteristics presented in this work.