|
|
 | | From: | wade | | Subject: | Ultrahigh field breakdown times | | Date: | 19 Dec 2004 05:30:31 GMT |
|
|
 |
Hi all,
I'm looking at a nanoelectronic device that may require electric fields
in the range from from 1E9 to 1E11 V/m. These fields are very high -
the 1E9 end of the range is where you'd expect to see vacuum breakdown
for any conductor I've found data for. However, the voltage need only
be applied for a very short time - pulses of 1E-11 to 1E-14 seconds.
I'm just speculating, but is it possible that with such a short time
scale the surface, while it may start field emitting, may survive
intact?
I understand that the destructive aspects of breakdown don't occur
until joule heating from field emission current gets things cooking.
I would be very interested if anyone has or knows of any research
on very high field but picosecond duration vacuum discharge
experiments.
Thanks,
Wade
|
|
| | From: | John Larkin | | Subject: | Re: Ultrahigh field breakdown times | | Date: | 19 Dec 2004 22:57:52 GMT |
|
|
|
On 19 Dec 2004 05:30:31 GMT, "wade"
wrote:
>
>Hi all,
>
>I'm looking at a nanoelectronic device that may require electric fields
>in the range from from 1E9 to 1E11 V/m. These fields are very high -
>the 1E9 end of the range is where you'd expect to see vacuum breakdown
>for any conductor I've found data for. However, the voltage need only
>be applied for a very short time - pulses of 1E-11 to 1E-14 seconds.
>
>I'm just speculating, but is it possible that with such a short time
>scale the surface, while it may start field emitting, may survive
>intact?
>I understand that the destructive aspects of breakdown don't occur
>until joule heating from field emission current gets things cooking.
>
>I would be very interested if anyone has or knows of any research
>on very high field but picosecond duration vacuum discharge
>experiments.
>
>Thanks,
>Wade
>
Tomographic atom probes apply a high negative field to a sharp
specimen tip and rip ions off for analysis. Tip radius is roughly 100
nm, and one usually applies a negative pulse of around 2KV on top of a
roughly 8KV dc bias, for a ns or so. I make pulsers to do this. Google
"atom probe".
For electron emission, lower positive voltages can yank electrons out
of very sharp tips, but the tips tend to erode and get contaminated if
the vacuum isn't very good. Field-emission sources are used in some
electron microscopes, but cold sources tend to be erratic emitters
except in ultrahigh vacuum. Warm, not-quite-thermionic tip emitters
are the compromise.
Electrical pulses in the 10 ps range are hard to make at any decent
voltage level. Actually, hard to make at any voltage level. And
virtually impossible to transport over usable distances.
Seems to me an intense laser pulse might have enough e-field to rip
electrons, but I don't have references.
John
|
|
|
