n-SiCd and n-SiPb Schottky junctions have been prepared by electrodeposition of Cd or Pb from acidic aqueous solutions onto H-terminated and C H3 -terminated n-type Si(111) surfaces. For both nondegenerately (n-) and degenerately (n+ -) doped H-Si(111) electrodes, Cd and Pb were readily electroplated and oxidatively stripped, consistent with a small barrier height (b) at the Si/solution and the Si/metal junctions. Electrodeposition of Cd or Pb onto degenerately doped C H3 -terminated n+ -Si (111) electrodes occurred at the same potentials as Cd or Pd electrodeposition onto H-terminated n+ -Si (111). However, electrodeposition on nondegenerately doped C H3 -terminated n-Si(111) surfaces was significantly shifted to more negative applied potentials (by -130 and -347 mV, respectively), and the anodic stripping of the electrodeposited metals was severely attenuated, indicating large values of b for contacts on nondegenerately doped n-type C H3 -Si (111) surfaces. With either Cd or Pb, current-voltage measurements on the dry, electrodeposited Schottky junctions indicated that much larger values of b were obtained on C H3 -terminated n-Si(111) surfaces than on H-terminated n-Si(111) surfaces. Chronoamperometric data indicated that C H3 -Si (111) 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 C H3 -Si surface modification.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry