MECHANISM OF ANODIC ELECTROLUMINESCENCE OF POROUS SILICON IN ELECTROLYTES

A mechanism of charge-carrier transfer from an electrolyte into porous silicon, which explains the efficient anodic electroluminescence of p orous silicon, is proposed and analyzed in detail. It is shown that wh en a current flows through the interface, electrically active particle s accumulate in the electrolyte - atomic hydrogen and oxygen, which wi th respect to porous silicon are efficient electron donors and accepte rs. Visible-range electroluminescence arises as a result of bipolar el ectron and hole injection from the electrolyte into high-resistance qu antum-well crystallites of porous silicon. It is shown that the overal l mechanism is the same for anodic and cathodic electroluminescence. T his explains the well-known similarity of these two processes. The det ailed physicochemical processes, which are the basis for anodic lumine scence, are explained. (C) 1998 American Institute of Physics. [S1063- 7826(98)01705-0].