Quantum confinement in PbSe thin films electrodeposited by electrochemical atomic layer epitaxy (EC-ALE)

PbSe is a IV-VI compound semiconductor with a narrow band gap (0.26 eV), used in photodetectors, photoresistors and photoemitters in the infrared (IR). This paper reports the first instance of PbSe formation by electrochemical atomic layer epitaxy (EC-ALE). The film's composition and structure were characterized using electron probe microanalysis (EPMA) and X-ray diffraction (XRD), respectively. The optical proper-ties were studied via infrared absorption measurements. Films were stoichiometric via EPMA, a Pb/Se ratio of one. XRD indicated the expected rock salt structure for PbSe, and a preferred (2 0 0) orientation. IR adsorption studies, of films grown with 10-50 cycles, showed strong blue shifts of the fundamental absorption edge, which was believed to result from quantum confinement in the thin films. (C) 2003 Elsevier Ltd. All rights reserved.