Magnesium-doped Cuprous Oxide (Mg:Cu2O) thin films as a ... · Magnesium-doped Cuprous Oxide...

Motivation

Results

• Successful  incorporation  of  Mg  on  Cu2O  thin  7ilms  by  MOCVD  with  a  thickness  below  100  nm;  • FTIR  con7irms  the  presence  of  Mg-­‐O  bonds;  • Elemental  quanti7ication  by  EDS  shows  Mg/Cu  ratios  2  to  3  times  lower  than  Mg  molar  mass  in  the  original  solution;  

•   The  predicted  changes  in  transparency  [Nolan  2008]  were  not  obtained  by  this  cation  incorporation;  • For  7ilms  with  high  Mg  content,  the  resistivity  is  reduced  7ive  times,  from  53  Ω.cm  to  11  Ω.cm.  The  causes  can  be  attributed  to:  

Ø Different  microstructure:  Larger  grains    –  Higher  mobility.  Ø Higher  amount  of  copper  vacancies  –  More  charge  carriers.    

Conclusions

References : Nolan, M. Chemistry of Materials, 2008. 20(17): p. 5522-5531.    http://www.doyouknow.in/Articles/images/201112231235452410290.png  

Magnesium-doped Cuprous Oxide (Mg:Cu2O) thin films as a transparent p-type

semiconductor oxide J. Resende1,2*, C. Jiménez1, N. D. Nguyen2, J. L. Deschanvres1

1 Laboratoire des Matériaux et du Génie Physique, Univ. Grenoble Alpes 2 SPIN Lab, Department of Physics, University of Liège

*joao.resende@grenoble-inp.fr

O  Cu  

Mg  

Reduced  Cu-­‐Cu  interactions  

Larger  band  gap  

Higher  transparency    

Higher  p-­‐type  conductivity  

Cu2O  cubic  structure  

Experimental

MOCVD  scheme  

Precursors:  Cu  (acac)2    c=0.02  mol.L-­‐1                                  Mg  (acac)2    c=  0  -­‐  0.01  mol.L-­‐1  

Solvent:  Butanol;      Deposition:  T=350  ºC;  t=60  min;  rate=2  ml.min-­‐1  

Carrier  gas:  Ar  5  L.min-­‐1    Acceleration  gas:  O2  4  L.min-­‐1    Annealing  Treatment:  1  hour  under  Air;  T=  250ºC  

Optical  Appearance   SEM  

Transmittance   Electrical  Properties  

Mg:Cu2O  thin  &ilms  deposited  on  glass  and  silicon  

Visible  Transmittance  around  50%  Eg  ~  2,2eV  

Decreasing  behavior  of  sheet  resistance  and  electrical  resistivity  with  increasing  content  of  Mg  P-­‐type  conduction  con&irmed  by  Hall  Effect    

FTIR  

Mg-­‐O  bond  detected  at  436  cm-­‐1  

Raman  

Cubic  Cu2O  phase  detected  

Mg/Cu  in  

solution  (%)  

Mg/Cu  in  

Bilm  (%)  

Thickness  

(nm)  

0   -­‐   86  

5   2.5   45  

10   3   97  

25   7   52  

50   20   77  

EDS  

Mg  detection  by  EDS  and  Mg/Cu  ratio  quanti&ication    

Mg/Cu  molar  ratio:    0%    5%    10%    25%  50%  

Larger  grains  with  the  increase  of  Mg  content;  Thickness  below  100  nm