DETERMINATION OF FERMI-LEVEL OF BI2SR2(Y1-XCAX)CU2OY AS A FUNCTION OFCALCIUM AND OXYGEN CONTENTS BY ELECTROCHEMICAL METHOD

From the electrochemical equilibrium potential of Bi2Sr2(Y1-xCax)Cu2Oy (BSYCCO), the Fermi level and the work function were determined as a function of excess oxygen content by. As by increased, the Fermi level descended steeply in the region of x = 0.0 similar to 0.1 and slightl y in the region of x = 0.5 similar to 1.0. The Fermi level for x = 1.0 (Delta y = 0.23) was 0.60 eV lower than that for x = 0.0 (Delta y = - 0.05). The dependence of the Fermi level on Delta y was consistent wit h the result of the UPS measurement. The result was well interpreted i n terms of a semiconductor model. (C) 1998 Published by Elsevier Scien ce B.V. All rights reserved.