Electrodeposition of PbSe onto n-Si(1 0 0) wafers

PbSe was electrodeposited onto monocrystalline n-Si(1 0 0) wafers from 50 mM Pb(NO3)2 + 2 mM SeO2 + 0.1 M HNO3 solution. The mechanism of PbSe electrocrystallization on n-Si was studied. At initial stage, 3D Pb and 3D Se nuclei are simultaneously codeposited onto Si at potentials more negative than Si flat band potential and chemically interact resulting in PbSe formation. When n-Si/PbSe heterostructure is formed, the overvoltage of bulk lead deposition increases, as a result of redistribution of electrode potential. Further growth of PbSe is realized due to underpotential deposition (UPD) of Pb and overpotential deposition (OPD) of Se onto formed PbSe nuclei. With Pb UPD shift increase, amorphous Se inclusion is registrated in the deposit. When 2D Pb nucleation mechanism is changed to 3D mode, metal Pb cubic phase is codeposited with PbSe. Electrodeposition of PbSe onto n-Si is irreversible. PbSe anodic stripping does not take place in the dark due to the barrier on solid interface. Oxidation of PbSe on n-Si is observed only under illumination, when photoholes are generated in silicon substrate.