[SI-LIST] Re: Subject: A Question on Electrons and Holes mobility
- From: "Lynne D. Green" <lgreen22@xxxxxxxxxxxxxx>
- To: si-list@xxxxxxxxxxxxx
- Date: Tue, 19 Jun 2012 22:23:29 -0700
"Holes" are like bubbles in water. Holes prefer
to rise in energy until they reach the top of the
valence band. For both bubbles and holes, they
can be described in terms of effective mass and
energy.
The carriers (electrons in conduction band, holes
in valence band, bubbles in water) act as "free"
carriers. They do not simply "hop" from one atom
(or water molecule) to the next. This has to do
with quantum properties energy bands compared to
discrete energy levels.
Electrons move more easily than holes because of
the quantum properties of the crystal lattice.
- Lynne
PS:
- A Google search for "Semiconductor Physics"
found several books.
- Unusual fact: Sometimes, the electron energy
diagram shows a region of negative mass (example:
GaAs). This quantum effect results in tunneling
between two regions of positive mass.
"IBIS training when you need it, where you need it."
Dr. Lynne Green
Green Streak Programs (and retired EE prof)
http://www.greenstreakprograms.com
425-788-0412
lgreen22@xxxxxxxxxxxxxx
On 6/19/2012 9:36 PM, Chaitanya Satuluri wrote:
> Yes. There is no holes in the world.
>
> chaitanya
>
> -----Original Message-----
> From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On
> Behalf Of Tesla
> Sent: Wednesday, June 20, 2012 8:04 AM
> To: sen.velmurugan@xxxxxxxxxx
> Cc: si-list@xxxxxxxxxxxxx
> Subject: [SI-LIST] Re: Subject: A Question on Electrons and Holes mobility
>
> Are there really "holes" in this world. it is actually electrons in moving.
>
> Tesla.
>
>
>
>
> At 2012-06-20 02:15:51,"Sen Velmurugan"<sen.velmurugan@xxxxxxxxxx> wrote:
>> I hope you agree that, An electron only travel to next atom not to
>> subsequent atom. That is.... due to Potential difference impressed on
>> the medium, a new electron is kicked in to an atom, then a older atom
>> kicked out into next atom, so it is a chain reaction.
>>
>> Holes exist only in a semi conductor a tighter medium called semi conductor.
>>
>> As the term implies, lattice is an highly uniformly structured medium,
>> where an electron has more room to move, that is not hindered by too
>> many free electrons, like an highspeed free way.
>>
>> For all the above mediums, you need appropriate potential difference to
>> make electron to take part in the conduction called current. No PD no
>> conduction, so mobility is like viscosity and PD is like pressure.
>>
>> Now, You need to use Bhors Atom model, shell energy level to make more
>> sense on the availability of electron for mobility for a given PD.
>> Hope I gave more perspective than an answer.
>> ~Sen
>>
>>
>> Date: Mon, 18 Jun 2012 11:34:50 +0530 Subject: [SI-LIST] A Question on
>> Electrons and Holes mobility From: Yagya Dutt Mishra
>> <ygdutt86.2@xxxxxxxxx> *Hello all :) * * * *A very small question
>> ...??*
>> * * *Electrons have higher mobility than holes.As of now i know these
>> reasons .. * * * *1) Since effective mass of electrons are less than
>> holes so electrons are more mobile as compared to holes.* * * *2)
>> (During the conduction) Electrons are present in conduction band and
>> holes are in valence band * *( because of the fact that electrons
>> jumped in the conduction band crossing the energy barrier and
>> generating a hole in the valence band).* *Since valence band is denser
>> as compared to conduction band (because of the presence of more charge
>> carriers) ,* *electrons can freely move while hole in the valence band
>> will face lots of attraction and repulsion.* * * *Now these two reasons
>> are well satisfying theoretically but practically (if there is any
>> other explanation emphasizing more on the solid physics of electrons
>> and
>> holes) by which i can understand more on this mobility issue please
>> tell
>> me.* * * *P.S : I have also read one thing "Electrons can move freely
>> in lattice as compared to holes" :( [still an unconvincing reason]* * *
>> * * *Thanks and Regards *
>>
>>
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