Structural defects at the semiconductor-ferroelectric interface

Structural defects at the interface between Pb 0.95 La 0.05 Ti 0.8 Zr 0.2 O 3 and La 1.85 Sr 0.15 CuO 4 were studied using the method of isothermal current relaxation. Two cases were considered: (a) the width of the defect-containing layer is much smaller than the width of the space-charge region and (b) the width of the defect-containing layer is greater than the width of the space-charge region. It is shown that, for the samples studied, the width of the defect-containing layer exceeds 50–100 Å, and the density of states for deep-level centers in the energy interval E v +(0.55–0.65) eV is about 3×10 20 cm −3 eV −1 ; this value corresponds to a surface state density of about 2×10 14 cm −2 eV −1 . It is shown that the density of states for deep-level centers increases from the interface into the depth of the semiconductor.