STRUCTURAL, OPTICAL AND TRANSPORT-PROPERTIES OF AG2S FILMS DEPOSITED CHEMICALLY FROM AQUEOUS-SOLUTION

Ag2S films were deposited chemically from silver nitrate and thiourea aqueous solutions at low temperature (40-80 degrees C). X ray diffract ion shows that the films are well crystallized with the acanthite stru cture. They display good optical properties with a direct band gap in the range 0.9-1.05 eV. These properties are improved by a thermal anne aling treatment in nitrogen at 250 degrees C for 1 h, with an increase in the band gap up to 1.07 eV. The effective mobility of carriers was measured by time-resolved microwave photoconductivity (TRMC). Values around 5-10 cm(2) V-1 s(-1) were estimated. A dependence on the deposi tion temperature is shown, with an optimal value around 60 degrees C.