Comparison of electron transport in polar materials for the models of low-density and high-density electron gas. Application to bulk GaN

• Published in: Semiconductor Physics Quantum Electronics & Optoelectronics
• Date: 2009
• Main Authors: Korotyeyev, V.V., Syngayivska, G.I., Kochelap, V.A., Klimov, A.A.
• Format: Article
• Language: English
• Published: Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України 2009
• Online Access: https://nasplib.isofts.kiev.ua/handle/123456789/118831
• Journal Title: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Cite this: Comparison of electron transport in polar materials
 for the models of low-density and high-density electron gas.
 Application to bulk GaN / V.V. Korotyeyev, G.I. Syngayivska, V.A. Kochelap and A.A. Klimov // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2009. — Т. 12, № 4. — С. 328-338. — Бібліогр.: 21 назв. — англ.

We analyzed the steady-state electron transport for bulk GaN in frame of two
 opposite approaches: the electron temperature approach that assumes a high-density
 electron gas and numerical single-particle Monte-Carlo method that assumes a lowdensity
 electron gas and does not take into account electron-electron (e-e) scattering. We
 have also presented an analytical solution of the Boltzmann transport equation based on
 diffusion approximation. The transport characteristics such as the drift velocity electric
 field, V d (E), and mean electron energy electric field, ε(E), have been calculated at
 nitrogen and room temperatures in the wide range of applied electric fields from zero
 fields up to runaway ones (~100 kV/cm) for both approaches. Our calculations were
 performed for doped semiconductor with equal impurity and electron concentrations,
 Ni = n =10¹⁶ cm⁻³. The electron distribution functions in various ranges of applied
 fields have been also demonstrated. Within the range of heating applied fields 0–
 300 V/cm, we found a strong difference between the transport characteristics obtained by
 means of the balance equations (electron temperature approach) and Monte-Carlo
 procedure. However, the Monte-Carlo calculations and diffusion approximation show a
 good agreement at 77 K. Within the range of moderate fields 1–10 kV/cm at 77 K, we
 established that the streaming effect can occur for low-density electron gas. In spite of
 significant dissimilarity of a streaming-like and a shifted Maxwellian distribution
 functions, the calculated values of Vd(E) and ε(E) show similar sub-linear behavior
 as the functions of the applied field E. In the high-field range 20–80 kV/cm, the
 streaming effect is broken down, and we observe practically linear behavior of both
 Vd(E) and ε(E) for both approaches. At higher fields, we point out the initiation of
 the runaway effect.