Studies on the electroluminescence of porous silicon in formic acid-sodiumformate solution at positive biases

The electroluminescence of porous silicon in formic acid and sodium formate solution at positive biases was investigated by luminescence spectrometer. It was discovered that the blue shift for peak wave lengths of electrolumi nescence occurred when the positive bias was increased. The emitted photon energy depended linearly on the positive biases, the slope of which was in agreement with that of elelctroluminescence at negatively biased condition. It was shown by scanning probe technique that there was close relation bet ween luminescence properties of porous silicon and its surface images. It w as suggested that the electroluminescence of porous silicon in the solution of formic acid and sodium formate stemmed from the oxidation of Si-H bonds on the surface of porous silicon. The voltage tunable emitting for porous silicon in formic acid - sodium formate solution at positive biases was rev ealed, which could be explained by the quantum confinement effect.