Influence of substrates porosity on the optical behavior of Zn 3 P 2 nanorod thin films I.K. El Zawawi a,⇑ , A. Abdel Moez a , T.R. Hammad b , R.S. Ibrahim a a Solid State Physics Department, National Research Centre, 12311 Dokki, Cairo, Egypt b Physics Department, Faculty of Science, Helwan University, Helwan, Egypt article info Article history: Received 26 June 2014 Accepted 1 July 2014 Available online 9 July 2014 Keywords: Zn 3 P 2 Nanorod films Transmission Electron Microscope (TEM) Structural properties Optical properties abstract Zn 3 P 2 nanostructural films were prepared by inert gas condensa- tion technique with constant argon gas flow rate of 3  10 1 Torr, 300 K substrate temperature and film thickness of 50 nm. The films were deposited on different porosity glass substrates. The porosity of substrates carried out by etching with dilute HF acid, was detected through the average pore size estimated from SEM image. The X-ray diffraction (XRD) patterns showed that the deposited films have nanocrystalline tetragonal structure with broad lines (400) and (303). The Transmission Electron Microscope (TEM) micro graphs showed that, these investigated films deposited on untreated glass substrates have nanorod particles with length of 41.2 nm and 5.4 nm width. The porosity of the used substrate affects strongly the optical behavior of the Zn 3 P 2 nanorod films. The optical transmission and reflection of Zn 3 P 2 thin films depos- ited on substrates with different time of etching were measured and showed highest absorption spectra for films of highest sub- strate porosity. The optical energy gap decreased with increasing porosity of substrates. The porosity of substrates affects the oscil- lating energy, dispersion energy and oscillator strength. The ratio of free carrier concentration/effective mass (N/m / ) were deter- mined for all investigated samples. Ó 2014 Published by Elsevier Ltd. http://dx.doi.org/10.1016/j.spmi.2014.07.001 0749-6036/Ó 2014 Published by Elsevier Ltd. ⇑ Corresponding author. Tel.: +20 01002337514. E-mail address: enaselza1@yahoo.com (I.K. El Zawawi). Superlattices and Microstructures 75 (2014) 183–194 Contents lists available at ScienceDirect Superlattices and Microstructures journal homepage: www.elsevier.com/locate/superlattices