College of Education for Pure Science

Master Thesis Viva in the College of Education for Pure Science entitled ” Calculation of the transport distribution of compound Semiconductors”The College of Education for Pure Science, University of Mosul, has done the Master Thesis Viva entitled ” Calculation of the transport distribution of compound Semiconductors “,On Sunday, February 5, 2023, the College staff including the respected Dean of the College, Assistant Professor Dr. Qais Ismail Ibrahim, the Honorable Scientific Associate and Administrative Associate, the Honorable Head of the Department of Physics, and a number of the college’s teachers were attended the viva. In this study, presented by the Master student Noora Anwar Mohammed Jamil in the Department of Physics, distribution function of the compound semiconductor gallium arsenide GaAs was calculated using the semi-classical Boltzmann equation for the transport of charge carriers (electrons) in the central low energy <000>  and for a range of low electric fields (0.3-1)E0 relative to the threshold field (E0 = 5.95Kv/cm). Obtaining a highly efficient distribution function requires building a technique that combines the analytical method and the numerical method to solve the Boltzmann transition equation. The analytical method involving the Legendre polynomial was used, which included the introduction the effect of polar optical scattering as a basic scattering mechanism in our work, in addition to the effect of non-parabolic band with spherical energy surfaces in the central valley. The resulting equation is a partial differential equation of the second order that has been solved numerically after performing the separation of variables using the direct matrix method in energy space. This equation can be solved using MATLAB software. The resulting distribution function can be used to calculate the electron energy rate and drift velocity as functions of the applied low fields.A system with dimensions of 360 × 360 was built, as the rate of change in energy  = 0.001. We tested the system by applied low electric fields, and the obtained distribution function had a Maxwellian distribution at very low fields, and it shifted from the Maxwellian distribution at higher fields close to the threshold field. We studied the transport properties of electrons, which includes calculating the average energy of electrons as a function of the low electric field, as the change in the average energy of electrons was very slight. We calculated the drift velocity as a function of the low fields at room temperature and at low temperatures, the electron drift velocity is affected by the field change and increases nonlinearly within this range of low fields and we found that the drift velocity curve with the field exhibits the same behavior for all low temperatures.The Viva committee was chaired by Prof. Dr. Laith Mohammed Saadoun / University of Mosul/ College of Science and the membership of Assist. Prof. Dr. Nawfal Youssef Jamil/ Noor University College, Lecturer Dr. Siham Younis Mustafa/ University of Mosul/ College of Education for Pure Sciences and under the supervision and membership of Lecturer. Dr. Ali Abbas Mohammed Salih/ University of Mosul/ College of Education for Pure Sciences.