Does a wide bandgap JFET glow under forward bias?...

T

Tim Williams

Guest
Yes.
https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3234138/#msg3234138

Tim

--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/
 
On Tuesday, September 15, 2020 at 1:27:45 PM UTC-7, Tim Williams wrote:
Yes.
https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3234138/#msg3234138
Click to expand...

Maybe. A SiC item is not just \'wide bandgap\', but DIRECT bandgap in nature; there\'s
no highspeed way for multistep recombination to far outpace the one-step-light-emitting
that causes the blue glow.
 
On Tue, 15 Sep 2020 15:27:38 -0500, \"Tim Williams\"
<tiwill@seventransistorlabs.com> wrote:

Yes.
https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3234138/#msg3234138

Tim
Click to expand...

I recall pictures of bipolar transistors emitting weak white light.
Pease?
 
On 2020-09-17 13:35, John Larkin wrote:
On Tue, 15 Sep 2020 15:27:38 -0500, \"Tim Williams\"
tiwill@seventransistorlabs.com> wrote:

Yes.
https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3234138/#msg3234138

Tim

I recall pictures of bipolar transistors emitting weak white light.
Pease?
Click to expand...

CMOS does it too--google mcmanus \"picosecond imaging circuit analysis\"

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
 
torsdag den 17. september 2020 kl. 19.35.47 UTC+2 skrev John Larkin:
On Tue, 15 Sep 2020 15:27:38 -0500, \"Tim Williams\"
tiwill@seventransistorlabs.com> wrote:

Yes.
https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3234138/#msg3234138

Tim

I recall pictures of bipolar transistors emitting weak white light.
Pease?
Click to expand...

with enough power most components do ;)
 
On Thursday, September 17, 2020 at 10:35:47 AM UTC-7, John Larkin wrote:
On Tue, 15 Sep 2020 15:27:38 -0500, \"Tim Williams\"
tiw...@seventransistorlabs.com> wrote:

Yes.
https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3234138/#msg3234138

Tim

I recall pictures of bipolar transistors emitting weak white light.
Click to expand...

Pictures, but perhaps taken with an IR camera? There\'s a good quantum-mechanics reason to
expect that a silicon charge-carrier-injection across the bandgap does not make white
light, but (of course) an IR camera that picks up light is capable of visible-light in white
or false color as a readout option.

Pictures of emssion is possible. White emission is not.
 
On Thu, 17 Sep 2020 13:09:20 -0700 (PDT), whit3rd <whit3rd@gmail.com>
wrote:

On Thursday, September 17, 2020 at 10:35:47 AM UTC-7, John Larkin wrote:
On Tue, 15 Sep 2020 15:27:38 -0500, \"Tim Williams\"
tiw...@seventransistorlabs.com> wrote:

Yes.
https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3234138/#msg3234138

Tim

I recall pictures of bipolar transistors emitting weak white light.

Pictures, but perhaps taken with an IR camera? There\'s a good quantum-mechanics reason to
expect that a silicon charge-carrier-injection across the bandgap does not make white
light, but (of course) an IR camera that picks up light is capable of visible-light in white
or false color as a readout option.

Pictures of emssion is possible. White emission is not.
Click to expand...

Of course it is.

https://www.semitracks.com/reference-material/failure-and-yield-analysis/failure-analysis-die-level/light-emission.php

Reverse biased pn junctions represent a different situation. When a
small reverse bias is applied to a junction, the depletion region
widens, causing low current but a substantial electric field. As the
reverse bias is increased, the probability that a highly excited
electron will cross the junction increases. This will generate photons
from the recombination of carriers whose energies can be significantly
above the bandgap energy. The resulting emission spectrum will have a
significant tail which can extend into the visible wavelengths.
 
On 2020-09-17 22:09, whit3rd wrote:
On Thursday, September 17, 2020 at 10:35:47 AM UTC-7, John Larkin wrote:
On Tue, 15 Sep 2020 15:27:38 -0500, \"Tim Williams\"
tiw...@seventransistorlabs.com> wrote:

Yes.
https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3234138/#msg3234138

Tim

I recall pictures of bipolar transistors emitting weak white light.

Pictures, but perhaps taken with an IR camera? There\'s a good quantum-mechanics reason to
expect that a silicon charge-carrier-injection across the bandgap does not make white
light, but (of course) an IR camera that picks up light is capable of visible-light in white
or false color as a readout option.

Pictures of emssion is possible. White emission is not.
Click to expand...

The light was emitted by an EB junction in reverse breakdown.
Many years ago, after reading Pease\'s piece on the subject, I
opened up a transistor in a TO-18 can to take a look. The light
was whitish. That surprised me. I expected monochromatic light.

Jeroen Belleman
 
On Thu, 17 Sep 2020 22:33:45 +0200, Jeroen Belleman
<jeroen@nospam.please> wrote:

On 2020-09-17 22:09, whit3rd wrote:
On Thursday, September 17, 2020 at 10:35:47 AM UTC-7, John Larkin wrote:
On Tue, 15 Sep 2020 15:27:38 -0500, \"Tim Williams\"
tiw...@seventransistorlabs.com> wrote:

Yes.
https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3234138/#msg3234138

Tim

I recall pictures of bipolar transistors emitting weak white light.

Pictures, but perhaps taken with an IR camera? There\'s a good quantum-mechanics reason to
expect that a silicon charge-carrier-injection across the bandgap does not make white
light, but (of course) an IR camera that picks up light is capable of visible-light in white
or false color as a readout option.

Pictures of emssion is possible. White emission is not.


The light was emitted by an EB junction in reverse breakdown.
Many years ago, after reading Pease\'s piece on the subject, I
opened up a transistor in a TO-18 can to take a look. The light
was whitish. That surprised me. I expected monochromatic light.

Jeroen Belleman
Click to expand...

With tens or hundreds of volts c-e, I\'d expect a normally biased
transistor to emit some visible light.

Zeners, too.
 
Tim Williams wrote:

> Yes.

Nuts do it as well, so why shouldn\'t a JFET?

https://i.imgur.com/WxqQIEB.jpg

https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3234138/#msg3234138
Click to expand...


Both effects could probably be combined in a fancy way.

Best regards, Piotr
 
On Thursday, September 17, 2020 at 1:29:46 PM UTC-7, John Larkin wrote:
On Thu, 17 Sep 2020 13:09:20 -0700 (PDT), whit3rd <whi...@gmail.com
wrote:

I recall pictures of bipolar transistors emitting weak white light.

Pictures, but perhaps taken with an IR camera? There\'s a good quantum-mechanics reason to
expect that a silicon charge-carrier-injection across the bandgap does not make white
light, but (of course) an IR camera that picks up light is capable of visible-light in white
or false color as a readout option.

Pictures of emssion is possible. White emission is not.
Of course it is.

https://www.semitracks.com/reference-material/failure-and-yield-analysis/failure-analysis-die-level/light-emission.php

Reverse biased pn junctions represent a different situation. When a
small reverse bias is applied to a junction, the depletion region
widens, causing low current but a substantial electric field. As the
reverse bias is increased, the probability that a highly excited
electron will cross the junction increases.
Click to expand...

Yes, that\'s certainly possible. The top post, though, specified \'forward bias\'
and adding in a fluorescence due to higher energy electrons (an electron-beam
probe could do it, too) is entirely a different kettle of fish.
 
Lasse Langwadt Christensen wrote:

> with enough power most components do ;)

I have never been able to go past the yellow part of the spectrum,
although the achieved quantum efficiency was rather impressive and would
not be adequately described by the word \"weak\"... ;-)

Best regards, Piotr
 
On 2020-09-17 16:09, whit3rd wrote:
On Thursday, September 17, 2020 at 10:35:47 AM UTC-7, John Larkin wrote:
On Tue, 15 Sep 2020 15:27:38 -0500, \"Tim Williams\"
tiw...@seventransistorlabs.com> wrote:

Yes.
https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3234138/#msg3234138

Tim

I recall pictures of bipolar transistors emitting weak white light.

Pictures, but perhaps taken with an IR camera? There\'s a good quantum-mechanics reason to
expect that a silicon charge-carrier-injection across the bandgap does not make white
light, but (of course) an IR camera that picks up light is capable of visible-light in white
or false color as a readout option.

Pictures of emssion is possible. White emission is not.
Click to expand...

Look up the PICA paper I posted. Hot-carrier emission is much bluer
than that.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
 
On 9/17/2020 5:46 PM, Piotr Wyderski wrote:
Tim Williams wrote:

Yes.

Nuts do it as well, so why shouldn\'t a JFET?

https://i.imgur.com/WxqQIEB.jpg
Click to expand...

Ohhhh, you didn\'t mean peanuts or gonads, it seems.


https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3234138/#msg3234138


Both effects could probably be combined in a fancy way.

    Best regards, Piotr
Click to expand...
 
On 17/09/2020 6:35 pm, John Larkin wrote:
On Tue, 15 Sep 2020 15:27:38 -0500, \"Tim Williams\"
tiwill@seventransistorlabs.com> wrote:

Yes.
https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3234138/#msg3234138

Tim

I recall pictures of bipolar transistors emitting weak white light.
Pease?
Click to expand...

Back in 2015 in this group I posted these pics:

<https://www.dropbox.com/s/6rkc80amj2aybuk/Veb_Setup.jpg?dl=0>

<https://www.dropbox.com/s/2fvi5i6tsphp0yg/Veb_AvalancheLEQ.jpg?dl=0>

The e-b in breakdown junction light looked silvery-blue-gray to the
human eye but the phone camera image represents a different color so
possibly a strong IR component too?

piglet
 
On Fri, 18 Sep 2020 09:43:39 +0100, piglet <erichpwagner@hotmail.com>
wrote:

On 17/09/2020 6:35 pm, John Larkin wrote:
On Tue, 15 Sep 2020 15:27:38 -0500, \"Tim Williams\"
tiwill@seventransistorlabs.com> wrote:

Yes.
https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3234138/#msg3234138

Tim

I recall pictures of bipolar transistors emitting weak white light.
Pease?


Back in 2015 in this group I posted these pics:

https://www.dropbox.com/s/6rkc80amj2aybuk/Veb_Setup.jpg?dl=0

https://www.dropbox.com/s/2fvi5i6tsphp0yg/Veb_AvalancheLEQ.jpg?dl=0

The e-b in breakdown junction light looked silvery-blue-gray to the
human eye but the phone camera image represents a different color so
possibly a strong IR component too?

piglet
Click to expand...

All sorts of semis may glow, but most are potted in black epoxy.

It would be cool to zener a photodiode. They are specifically designed
for good optical paths into (thus out of) the semiconductor.

A forward-biased compound-semi photodiode probably has some, maybe
visible, LED effect.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard
 
https://www.researchgate.net/publication/327860836_Investigating_SiC_MOSFET_body_diode\'s_light_emission_as_Temperature-Sensitive_Electrical_Parameter
 
On 2020-09-18 21:03, Dmitriy Pshonkin wrote:
> https://www.researchgate.net/publication/327860836_Investigating_SiC_MOSFET_body_diode\'s_light_emission_as_Temperature-Sensitive_Electrical_Parameter

Measuring the photo current, and then displaying the value in mV?

The forward voltage of the photo diode will be very depending on
temperature (threshold, leakage will vary). The diode is placed on top
of the FET gel, so it\'s temperature will also have varied.

Apart from the fun fact that light has been observed, this research is
practically useless.

It should be mandatory to add a well-qualified electronics engineer to
scientific teams dabbling with electronics. And to review teams.

Arie
 
On Sat, 19 Sep 2020 14:19:17 +0200, Arie de Muynck
<no.spam@no.spam.org> wrote:

On 2020-09-18 21:03, Dmitriy Pshonkin wrote:
https://www.researchgate.net/publication/327860836_Investigating_SiC_MOSFET_body_diode\'s_light_emission_as_Temperature-Sensitive_Electrical_Parameter

Measuring the photo current, and then displaying the value in mV?

The forward voltage of the photo diode will be very depending on
temperature (threshold, leakage will vary). The diode is placed on top
of the FET gel, so it\'s temperature will also have varied.

Apart from the fun fact that light has been observed, this research is
practically useless.

It should be mandatory to add a well-qualified electronics engineer to
scientific teams dabbling with electronics. And to review teams.

Arie
Click to expand...

No, that would remove the substantial amusement available from many
scientific papers.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard
 
On 2020-09-17 20:20, John S wrote:
On 9/17/2020 5:46 PM, Piotr Wyderski wrote:
Tim Williams wrote:

Yes.

Nuts do it as well, so why shouldn\'t a JFET?

https://i.imgur.com/WxqQIEB.jpg


Ohhhh, you didn\'t mean peanuts or gonads, it seems.
Click to expand...

I saw that one with the caption, \"Extra heavy-duty Russian LED\".

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
 
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