Effects of frequency on Bi and Ni electrodepostion nano-wires?

[WayneL]

Hi

I have read a paper on Fabrication of highly ordered metallic nanowire
arrays by electrodeposition by Yin a Brown University, US. See link for a
copy of the paper.
http://optonano.engin.brown.edu/Publications/APL01039.pdf

This paper discusses, among other things, the deposition of Bi and Ni to
produce nanowires.

Yin grew nickel and bismuth nano-wire using AC electrodeposition for
applications of high density recording devices and sensors. Yin used an AAO
(self-ordered anodised aluminium oxide) film as the cathode and a graphite
bar as the anode. He states that electrodeposition of metal into the porous
alumina film directly following anodisation can take place only under AC
conditions. Producing either Bi or Ni nano-wires required different
conditions.
Yin also found that the frequency range used also affected the results
produced. Another point worth noting is that high quality deposition of Ni
could be obtained with AC frequencies from 10 to 750 Hz and for Bi the
optimum frequency range was between 10 and 100 Hz. He commented that this
was probably due to the double layer. However, if the double layer is the
main factor dictating the frequency response then surely the frequency he
stated would be a function of the electrode size? Thus his figure are
arbitrary as they do not have any dimensional data. And if he did use the
same size electrodes for both Bi and Ni deposition why would the frequencies
be different? Surely the double layer capacitance is the same for both
metals or am I missing something here or is the double layer capacitance a
function of the metal's atomic number? One thing that is obvious is that
Bi(83) is significantly heavier than Ni (28).

Could somebody possible help clear this up for me.

Cheers

Wayne

 

[boer]

Hi

I have read a paper on Fabrication of highly ordered metallic nanowire
arrays by electrodeposition by Yin a Brown University, US. See link for a
copy of the paper.
http://optonano.engin.brown.edu/Publications/APL01039.pdf

This paper discusses, among other things, the deposition of Bi and Ni to
produce nanowires.

Yin grew nickel and bismuth nano-wire using AC electrodeposition for
applications of high density recording devices and sensors. Yin used an AAO
(self-ordered anodised aluminium oxide) film as the cathode and a graphite
bar as the anode. He states that electrodeposition of metal into the porous
alumina film directly following anodisation can take place only under AC
conditions. Producing either Bi or Ni nano-wires required different
conditions.
Yin also found that the frequency range used also affected the results
produced. Another point worth noting is that high quality deposition of Ni
could be obtained with AC frequencies from 10 to 750 Hz and for Bi the
optimum frequency range was between 10 and 100 Hz. He commented that this
was probably due to the double layer. However, if the double layer is the
main factor dictating the frequency response then surely the frequency he
stated would be a function of the electrode size? Thus his figure are
arbitrary as they do not have any dimensional data. And if he did use the
same size electrodes for both Bi and Ni deposition why would the frequencies
be different? Surely the double layer capacitance is the same for both
metals or am I missing something here or is the double layer capacitance a
function of the metal's atomic number? One thing that is obvious is that
Bi(83) is significantly heavier than Ni (28).

Could somebody possible help clear this up for me.

Cheers

Wayne

The use of AC voltage is to overcome the barrier layer at the bottom of
the pores during the fabrication process, as stated in the paper. The
thinness/thickness of this non-porous layer presents a difficulty in DC
plating of the nanopores. This is *not* the double layer capacitance per
your post. The paper does discuss barrier thinning voltages compared to
older methods using dilute phosphoric acid etching to thin this physical
barrier layer. Yes, our lab did indeed find differences in AC plating
frequencies of nanopores dependent on the metal to be deposited.

boer

 

[WayneL]

Hi Boer,
Thanks for responding.
Have you got an explanation for the difference in frequencies for the two
metals? e.g. why are they different if the electrode are of the same size?
Also the paper mentions that other metal were tested and they also showed to
have different frequencies. Have you got this data to hand?

Wayne

 

[WayneL]

Hi Boer,
Thanks for responding.
Have you got an explanation for the difference in frequencies for the two
metals? e.g. why are they different if the electrode are of the same size?
Also the paper mentions that other metal were tested and they also showed to
have different frequencies. Have you got this data to hand?

Wayne

 

[WayneL]

Hi Boer,
Thanks for responding.
Have you got an explanation for the difference in frequencies for the two
metals? e.g. why are they different if the electrode are of the same size?
Also the paper mentions that other metal were tested and they also showed to
have different frequencies. Have you got this data to hand?

Wayne

 

[boer]

Hi Boer,
Thanks for responding.
Have you got an explanation for the difference in frequencies for the two
metals? e.g. why are they different if the electrode are of the same size?
Also the paper mentions that other metal were tested and they also showed to
have different frequencies. Have you got this data to hand?

Wayne

Hi Wayne,
I am still studying the paper you referenced. Our lab pursued these
templated wires a decade ago for field emission and photocathode
applications. We found engineering challenges in pore spacing and
thinning the barrier at the pore metal interface. The explanation for
your question I believe is in the thinning of the barrier alumina at the
pore/substrate interface. Most investigations in frequency dependence
and repeatable e-plating focused on this barrier thinning at the
interface. Pore widening and and barrier thinning methods were
thoroughly investigated by a number of labs at the time.

boer