Reversible Luminescence Quenching of Porous Si by Solvents

Abstract

ABSTRACTInteraction of the solvents tetrahydrofuran, diethyl ether, methylene chloride, toluene, o-xylene, benzene, and methanol with luminescent porous n- Si (PS) results in reversible quenching of the luminescence associated with this material. The degree of quenching ranges from 99% – 50%, and scales with solvent dipole moment. Reaction with gaseous Cl2, Br2, or I2 results in irreversible quenching, associated with a surface reaction that removes Si-H bonds. Total luminescence quenching is observed on treatment of a PS wafer with a solution of the electron donor ferrocene in toluene, suggesting that charge transfer quenching may also be operative in this material. Luminescence is partially recovered by rinsing the PS in pure toluene. The data show that photoluminescence of PS is highly sensitive to surface adsorbates, suggesting that carrier trapping is easily induced in this material.