THICKNESS DEPENDENT PROPERTIES OF CHEMICALLY DEPOSITED BI2S3 THIN-FILMS

Thin films of Bi2S3 with different thicknesses were prepared by the ch emical deposition method from an aqueous acidic bath using thiosulfate as a sulfide ion source. The effect of film thickness on the optical, structural and electrical properties was studied. A shift of 0.6 eV i n the optical bandgap energy, E-g, and a decrease in electrical resist ivity from 2.8 x 10(4) to 5 x 10(3) Ohm cm and an increase in grain si ze of Bi2S3 crystallites from 5.2 to 8.0 nm were observed when the thi ckness was varied from 52.7 to 220 nm. These changes are attributed to the quantum size effect in semiconducting films. (C) 1997 Elsevier Sc ience S.A.