Robust p-type doping of copper oxide using nitrogen implantation

We demonstrate robust p-type doping of Cu2O using low/medium energy ion implantation. Samples are made by controlled oxidation of annealed Cu metal foils, which results in Cu2O with levels of doping close to intrinsic. Samples are then implanted with nitrogen ions using a kinetic energy in the few keV range. Using this method, we are able to produce very high levels of doping, as evidenced by a 350 meV shift in the Fermi level towards the VB maximum. The robustness of the nitrogen implanted samples are tested by exposing them to atmospheric contaminants, and elevated temperatures. The samples are found to survive an increase in temperature of many hundreds of degrees. The robustness of the samples, combined with the fact that the materials used are safe, abundant and non-toxic and that the methods used for the growth of Cu2O and N+ implantation are simple and cheap to implement industrially, underlines the potential of Cu2O:N for affordable intermediate band photovoltaics.

[1]  J. Pierson,et al.  Nitrogen chemical state in N-doped Cu2O thin films , 2017 .

[2]  T. Miyata,et al.  Efficiency enhancement using a Zn1−xGex-O thin film as an n-type window layer in Cu2O-based heterojunction solar cells , 2016 .

[3]  S. Limpijumnong,et al.  Identification of nitrogen acceptor in Cu2O: First-principles study , 2015 .

[4]  Xiaodong Yang,et al.  Resonant photoemission spectroscopy for intermediate band materials , 2015 .

[5]  V. Roy,et al.  The n-type conduction of indium-doped Cu2O thin films fabricated by direct current magnetron co-sputtering , 2015 .

[6]  Kevin P. Musselman,et al.  Fabrication of ZnO/Cu2O heterojunctions in atmospheric conditions: improved interface quality and solar cell performance , 2015 .

[7]  Xiaodong Yang,et al.  Cr-doped ZnS for intermediate band solar cells , 2013, 2013 IEEE 39th Photovoltaic Specialists Conference (PVSC).

[8]  P. Scardi,et al.  Nitrogen doped Cu2O: A possible material for intermediate band solar cells? , 2012 .

[9]  I. Bertóti.  Nitrogen modified metal oxide surfaces , 2012 .

[10]  C. Pu,et al.  Growth behavior and optical properties of N-doped Cu2O films , 2011 .

[11]  B. Cowie,et al.  The Current Performance of the Wide Range (90-2500 eV) Soft X-ray Beamline at the Australian Synchrotron , 2010 .

[12]  J. Ziegler,et al.  SRIM – The stopping and range of ions in matter (2010) , 2010 .

[13]  T. Morikawa,et al.  Optical bandgap widening of p-type Cu2O films by nitrogen doping , 2009 .

[14]  P. Hofmann,et al.  Surface-sensitive conductance measurements , 2009, Journal of physics. Condensed matter : an Institute of Physics journal.

[15]  Q. Gao,et al.  Characterization of molecular nitrogen in III-V compound semiconductors by near-edge x-ray absorption fine structure and photoemission spectroscopies , 2008 .

[16]  Ilia Platzman,et al.  Oxidation of Polycrystalline Copper Thin Films at Ambient Conditions , 2008 .

[17]  U. Diebold,et al.  Surface studies of nitrogen implanted TiO2 , 2007 .

[18]  Alex Zunger,et al.  Origins of the p-Type Nature and Cation Deficiency in Cu2O and Related Materials , 2007 .

[19]  Antonio Luque,et al.  Intermediate bands versus levels in non-radiative recombination , 2006 .

[20]  Francesca Sarto,et al.  Heterojunction solar cell with 2% efficiency based on a Cu2O substrate , 2006 .

[21]  Junqiao Wu,et al.  Highly Mismatched Alloys for Intermediate Band Solar Cells , 2005 .

[22]  C. Klingshirn,et al.  Exciton lifetime, Auger recombination, and exciton transport by calibrated differential absorption spectroscopy in Cu 2 O , 2002 .

[23]  S. Ishizuka,et al.  Nitrogen Doping into Cu2O Thin Films Deposited by Reactive Radio-Frequency Magnetron Sputtering , 2001 .

[24]  Z. Q. Liu,et al.  Thermal stability of copper nitride films prepared by rf magnetron sputtering , 1998 .

[25]  A. Luque,et al.  Increasing the Efficiency of Ideal Solar Cells by Photon Induced Transitions at Intermediate Levels , 1997 .

[26]  B. Rai,et al.  Cu2O solar cells: A review , 1988 .

[27]  P. Couturier.  Japan , 1988, The Lancet.

[28]  P. M. Raole,et al.  XPS studies at various temperatures of nitrogen implanted copper , 1985 .

[29]  L. Papadimitriou,et al.  Photovoltaic properties of sputtered n-CdO films on p-Cu2O , 1983 .

[30]  L. C. Olsen,et al.  Experimental and theoretical studies of Cu2O solar cells , 1982 .

[31]  J. Biersack,et al.  A Monte Carlo computer program for the transport of energetic ions in amorphous targets , 1980 .

[32]  W. A. Dench,et al.  Quantitative electron spectroscopy of surfaces: A standard data base for electron inelastic mean free paths in solids , 1979 .

[33]  H. Queisser,et al.  Detailed Balance Limit of Efficiency of p‐n Junction Solar Cells , 1961 .

[34]  W. Stickle,et al.  Handbook of X-Ray Photoelectron Spectroscopy , 1992 .