Behavior of Electrodeposited Cd and Pb Schottky Junctions on CH3-Terminated n-Si(111) Surfaces

Abstract

and Schottky junctions have been prepared by electrodeposition of Cd or Pb from acidic aqueous solutions onto H-terminated and -terminated n-type Si(111) surfaces. For both nondegenerately (n-) and degenerately doped H–Si(111) electrodes, Cd and Pb were readily electroplated and oxidatively stripped, consistent with a small barrier height at the Si/solution and the Si/metal junctions. Electrodeposition of Cd or Pb onto degenerately doped -terminated electrodes occurred at the same potentials as Cd or Pd electrodeposition onto H-terminated . However, electrodeposition on nondegenerately doped -terminated n-Si(111) surfaces was significantly shifted to more negative applied potentials (by and , respectively), and the anodic stripping of the electrodeposited metals was severely attenuated, indicating large values of for contacts on nondegenerately doped n-type surfaces. With either Cd or Pb, current–voltage measurements on the dry, electrodeposited Schottky junctions indicated that much larger values of were obtained on -terminated n-Si(111) surfaces than on H-terminated n-Si(111) surfaces. Chronoamperometric data indicated that surfaces possessed an order-of-magnitude lower density of nucleation sites for metal electrodeposition than did H–Si(111) surfaces, attesting to the high degree of structural passivation afforded by the surface modification.