We used far-infrared transmission spectroscopy to probe the electrostatically induced charge carriers in a ZnO field-effect transistor. The carrier absorption spectrum exhibits a non-Drude, incoherent conduction behavior at low gate-source voltages (VGS <40 V), which evolves toward a standard Drude behavior as VGS is increased. This change is explained successfully by a generalized Drude model. We find that the interface carriers undergo strong backscattering collisions during the channel conduction and the microscopic scattering angle changes with VGS.
Bibliographical noteFunding Information:
We thank D. Basov for useful discussions and D. Schmadel for careful reading of the manuscript. This work was supported by BK21 through the Human Resource Development for the computational physics team of the Univ. of Seoul. Seongil Im and Kitae Kim acknowledge the financial support from Brain Korea 21 Project of the Yonsei University.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)