The research group of Prof. Kawasaki in WPI-AIMR has successfully demonstrated the
systematic control of two-dimensional (2D) electron transport at oxide heterointerfaces using
Schottky-gating via conducting polymer, PEDOT:PSS (poly(3,4-ethylenedioxythiophene):
poly(styrenesulfonate)). PEDOT:PSS works excellent Schottky contact electrode on oxide
semiconductor ZnO because of clean organic-inorganic interface with abruptness both in
crystallographic and electronic properties. In this study, a field-effect transistor shown in Fig. 1 was
fabricated by conventional molecular-beam epitaxy for MgZnO/ZnO heterostructures and spin
coating for PEDOT:PSS. 2D electron density and conductivity were systematically tuned by the
application of gate bias voltage at 2 K. In addition, we found interesting physical phenomenon of
insulator-to-metal transition at a certain gate bias as shown in Fig. 3. These achievements pave a
way for harmless, transparent, and low cost field-effect transistors. This work was performed for a
sample supplied from ROHM Co. Ltd. These results will be published in Advanced Materials at
November 25th, 2009.

Press Release