Optical properties of size quantized PbSe films chemically deposited on GaAs

¹ Department of Materials Engineering and the Ilse Katz Center for Nanoscience and Nanotechnology, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
² Research Institute for Technical Physics and Material Science, Hungarian Academy of Science, Budapest, 1121 Konkoly Th. u. 29-33, Hungary
³ Racah Institute of Physics and the Center for Nanoscience and Nanotechnology, the Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel

Corresponding author: ygolan@bgu.ac.il

Received: 7 June 2007
Revised: 9 September 2007
Accepted: 15 October 2007
Published online: 21 December 2007

Abstract

PbSe films were chemically deposited with a range of controlled microstructures, from nanocrystalline to monocrystalline films. The crystal size in the nanocrystalline films was controlled in a range 7 to 25 nm with a fairly narrow size distribution, which allowed fine-tuning of the PbSe energy gap. The optical properties of the films were investigated using infrared (IR) transmission and IR photoluminescence measurements. The nanocrystalline PbSe films showed single bandgap values in the technologically important near-IR region. Two bandgap values, corresponding to both bulk and confined nanocrystals, were obtained for films with mixed microstructure. Strong blue shifts in both the absorption and emission peaks of the nanocrystalline layers were obtained. The bandgaps of the PbSe films were found to be in good agreement with theoretical calculations. The results point out the potential of these films for nanoscale optical device applications operating in the near-IR range.