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Is zinc oxide a potential material for future high-power and high-frequency electron device applications? Poppy Siddiqua1, Walid A. Hadi1, Michael S. Shur2, and Stephen K. O’Leary1 1 School of Engineering, The University of British Columbia, Kelowna, British Columbia, Canada V1V 1V7 2 Department of Electrical, Computer, and Systems Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180-3590, U.S.A. ABSTRACT At the present moment, zinc oxide is primarily being used as an electronic material for low-field thin-film transistor and transparent conducting oxide device applications. In this paper, we present some recent results on the steady-state electron transport within zinc oxide suggesting that this material may also be considered as an alternative material to gallium nitride for highpower and high-frequency electron device applications. The expected device performance that may be obtained from zinc oxide-based devices is then projected and contrasted with that expected from gallium nitride-based devices. It is shown that zinc oxide-based devices have a slight advantage when compared with the case of gallium nitride. 1. INTRODUCTION Wide energy gap semiconductors, being in possession of higher saturation electron drift velocities, higher thermal conductivities, higher breakdown fields, and lower dielectric constants, are now well recognized as offering considerable potential for high-power and high-frequency electron device applications [1, 2]. Gallium nitride (GaN) is a wide energy gap semiconductor that has become the focus of much investigation in recent years [3]. Much of the research that has occurred on this material during the past decade has focused upon understanding, characterizing, and improving the material properties of this electronic material. As a result of this effort, a number of GaN-based wide energy gap semiconductor devices are in production today [4]. Zinc oxide (ZnO) is a II-VI compound semiconductor that has a wide and direct energy gap, 3.4 eV at room temperature, which is comparable to that exhibited by GaN [5]; the room temperature energy gap of GaN is 3.39 eV. Many of the current applications of ZnO employ this material in low-field settings. These include applications as the electronic material within thinfilm transistors and as a material for transparent conducting oxides. It is our expectation, however, given that it is a wide energy gap compound semiconductor, that with an improvement in its material properties, ZnO might also be considered as a material for high-power and highfrequency electron device applications, as GaN currently is. It is the purpose of this paper to investigate the plausibility of this premise. We first start with a summary of the basic material properties associated with ZnO, i.e., its energy gap and breakdown field strength, contrasting these ZnO properties with those associated with GaN, gallium arsenide (GaAs), and silicon (Si). Then, the steady-state velocityfield characteristic associated with ZnO is contrasted with that associated with GaN. Usi