Silicon DOI 10.1007/s12633-016-9457-1 ORIGINAL PAPER Fabrication and Characterization of a p-AgO/PSi/n-Si Heterojunction for Solar Cell Applications Nadir F. Habubi 1 · Ahmed N. Abd 2 · Mohammed O. Dawood 2 · A. H. Reshak 3,4 Received: 21 March 2016 / Accepted: 10 August 2016 © Springer Science+Business Media Dordrecht 2016 Abstract A p-AgO/PSi/n-Si heterojunction was deposited by high vacuum thermal evaporation of silver subjected to thermal oxidation at 300 ◦ C on porous silicon. Surface mor- phology and electrical properties of this structure have been studied. The X-ray diffraction (XRD) analysis reveals that the peaks at the (220) and (111) planes were dominated for the crystal quality of the AgO films. The band gap of the AgO films was found to be 2.2 eV and 3.2 eV . The positive sign of Hall effect confirms that the film was of p-type con- ductivity. The average grain size of pore was measured from the atomic force microscope (AFM) analysis and found to be around 32 nm. The responsivity photodetector after deposited AgO have revealed increasing in response. Keywords AgO · Thermal oxidation · Lifetime · Heterodiode · XRD · AFM · SEM  Nadir F. Habubi nadirfadhil@yahoo.com 1 Physics Department, Education Faculty, University of Al- Mustansiriyah, Baghdad, Iraq 2 Physics Department, Science Faculty, University of Al- Mustansiriyah, Baghdad, Iraq 3 New Technologies - Research Centre, University of West Bohemia, Univerzitni 8, 306 14 Pilsen, Czech Republic 4 Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis, Malaysia 1 Introduction Silver oxide (AgO) semiconductor films are known to dis- play p-type semiconductor properties with a bandgap in the range 1.20-3.4 eV [1]. Silver oxides crystallize out by a numerous types of crystal structures, leading to diverse of interesting physiochemical properties such as catalytic, electrochemical, electronic and optical properties [2]. It is known that the AgO phase was relatively steady at high oxygen pressures and at low temperatures. The AgO inhab- its different crystal systems such as cubic, monoclinic and tetragonal [3–5]. It is known that the silver, because of its d- shell electrons, exists in different oxidation states and forms several oxides for instance AgO, Ag 2 O, Ag 3 O, Ag 2 O 3 . The action of forming of these oxides depends upon the growth conditions/reaction kinetics, accessibility of oxygen in the growth chamber and the energy required for the oxidation. The surface morphology and the nucleation kinetics of the silver oxide rely on the kinetic energy of the particles (sil- ver and oxygen atoms or silver oxide molecules) access to the substrate [6]. Among the various metals, silver showed effective thermal conductivity , high electrical conductivity and can be synthesized into Ag based compounds with dif- ferent compositions. Silver is more interactive than gold or platinum therefore, silver is the most convenient candidate for various applications [7, 8]. These oxides have variant crystalline structures leading to a different physiochemi- cal, electrochemical, electronic, and optical properties. The most observable and stable phases are Ag 2 O and AgO [9]. AgO thin films can be synthesised by using various deposition processes such as thermal oxidation of silver films [10], thermal evaporation [11], electron beam evap- oration [12], pulsed laser deposition [13], chemical vapor