Final Report Page: 4 of 10
This report is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to Digital Library by the UNT Libraries Government Documents Department.
The following text was automatically extracted from the image on this page using optical character recognition software:
DE-EE0000577 Final Report
2A13+ + 60H -, A12Q34 + 3H20 (R3)
In addition to Al, Ga has also been attempted as a n-type dopant in ZnO to achieve low
resistivity. The precursor for Ga is Ga(NO3)3. The doping mechanism for Ga-doped ZnO is
similar to that of Al-doped ZnO, by co-precipitation as revealed by cyclic voltammetry.
In both Al-doped and Ga-doped cases, detailed studies of the sheet resistance of the
doped ZnO films as a function of Al(NO3)3 or Ga(NO3)3 concentration in the deposition solution
are carried out, in an attempt to minimize the resistivity of the doped ZnO films.
2) Task 3: Post-Deposition Annealing
This task for Al-doped and Ga-doped ZnO has been successfully completed. The
optimized post-deposition annealing conditions for Al-doped ZnO are found to be 200 C for 3
hours in air. The minimum sheet resistance for Al-doped ZnO achieved is 13.8 Q/w, which
occurs with an A3/Zn2+ ratio of 0.001 in the deposition solution. The corresponding resistivity
for the Al-doped ZnO is 8x10-4 Q-cm.
For Ga-doped ZnO, the optimum post-deposition annealing conditions are found to be
300 C for 2 hours in vacuum 4Torr). The minimum sheet resistance for Ga -doped ZnO
achieved is 7 Q/w and the corresponding resistivity of the Ga-doped ZnO is 3.8x10-4 Q-cm. This
meets the resistivity requirement for TCOs in solar cells. The sample is deposited in a solution
with a Ga3+/Zn2+ ratio of 0.0064.
3) Task 4: Investigation of Film Properties
Energy dispersion spectroscopy is carried out to determine the Al content in Al-doped
ZnO as a function of A3/Zn2+ ratio in the deposition solution. The Al/Zn ratio in the film
corresponding to the minimum sheet resistance of 13.8 Q/w is 0.02. Optical characterization
reveals high transmissivity (>80%) for Al-doped ZnO, which meets the transmissivity
requirement for TCOs.
For Ga-doped ZnO, energy dispersion spectroscopy reveals the Ga/Zn ratio in the film
corresponding to the minimum sheet resistance of 7 Q/w is 0.23. Optical characterization reveals
high transmissivity (80%) for Ga-doped ZnO. X-ray diffraction confirms that Ga-doped ZnO
deposited under the conditions described above is actually ZnO.
3.2 F-Doped ZnO
1) Task 2: Electrodeposition of F-Doped ZnO
This task has been completed. The deposition solution contains 0.5 M Zn(NO3)2 as the Zn
precursor and 0.6 M NaF as the F precursor, which meet the solubility requirement. The
complaxing agent used is EDTA (CiOH16N208) at 0.5 M. The solution pH is adjusted to 7 by
adding NaOH. It is found that 0.5-M EDTA allows the solution pH to be increased to ~10
without Zn(OH)2 precipitation. The solution temperature is 80 C. Cyclic voltammetry reveals
Total: 10 pages
Here’s what’s next.
This report can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Report.
Tao, Dr. Meng. Final Report, report, December 22, 2010; United States. (digital.library.unt.edu/ark:/67531/metadc833903/m1/4/: accessed October 23, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.