We study the steady-state and transient electron transport that occurs within wurtzite and zinc-blende indium nitride using a three-valley Monte Carlo simulation approach. For our steady-state results, we find that, for both cases, initially the electron drift velocity monotonically increases with the applied electric field strength, reaching a peak value followed by a region of negative differential mobility, and then a region of saturation. The peak fields are found to be around 30 kV/cm for the case of wurtzite indium nitride and about 50 kV/cm for the case of zinc-blende indium nitride, the corresponding peak and saturation electron drift velocities being around 5.6×107 and 1.2×107 cm/s for the case of wurtzite indium nitride and about 3.3×107 and 1.0×107 cm/s for the case of zinc-blende indium nitride. For the purposes of our transient electron transport analysis, we follow the approach of O'Leary et al. [Appl. Phys. Lett. 87, 222103 (2005)], and examine how an ensemble of electrons responds to the sudden application of a constant electric field. We find that the electrons within wurtzite indium nitride exhibit higher electron drift velocities and longer relaxation times than those within zinc-blende indium nitride. The device implications of these results are then discussed.

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Wide energy gap semiconductors are broadly recognized as promising materials for novel electronic and optoelectronic device applications. As informed device design requires a firm grasp of the material properties of the underlying electronic materials, the electron transport that occurs within the wide energy gap semiconductors has been the focus of considerable study over the years. In an effort to provide some perspective on this rapidly evolving and burgeoning field of research, we review analyzes of the electron transport within some wide energy gap semiconductors of current interest in this paper. In order to narrow the scope of this review, we will primarily focus on the electron transport that occurs within the wurtzite phases of gallium nitride, aluminum nitride, indium nitride, and zinc oxide in this review, these materials being of great current interest to the wide energy gap semiconductor community; indium nitride, while not a wide energy gap semiconductor in of itself, is included as it is often alloyed with other wide energy gap semiconductors, the resultant alloys being wide energy gap semiconductors themselves. The electron transport that occurs within zinc-blende gallium arsenide is also considered, albeit primarily for bench-marking purposes. Most of our discussion will focus on results obtained from our ensemble semi-classical three-valley Monte Carlo simulations of the electron transport within these materials, our results conforming with state-of-the-art wide energy gap semiconductor orthodoxy. A brief tutorial on the Monte Carlo electron transport simulation approach, this approach being used to generate the results presented herein, is also provided. Steady-state and transient electron transport results are presented. The evolution of the field, and a survey of the current literature, are also featured. We conclude our review by presenting some recent developments on the electron transport within these materials.

A three-valley Monte Carlo simulation approach is used in order to probe the transient electron transport that occurs within bulk wurtzite zinc oxide. For the purposes of this analysis, we follow O’Leary et al. [Solid State Commun. 150, 2182 (2010)], and study how electrons, initially in thermal equilibrium, respond to the sudden application of a constant applied electric field. We find that for applied electric field strength selections in excess of 300 kV/cm that an overshoot in the electron drift velocity is observed. An undershoot in the electron drift velocity is also observed for applied electric field strength selections in excess of 700 kV/cm, this velocity undershoot not being observed for other compound semiconductors, such as gallium arsenide and gallium nitride. We employ a means of rendering transparent the electron drift velocity enhancement offered by the transient electron transport, and then use the calculated dependence of the peak transient electron drift velocity on the applied electric field for the design optimization of short-channel high-frequency electron devices.

Articles you may be interested inSteady-state and transient electron transport within wurtzite and zinc-blende indium nitride