Dear friends...
Here are some queries regarding the nature of semiconductors,with respect to RS2:
1.What are the properties of semiconductors in general,with respect to their time motion pattern?
2.What is the mechanism of operation of a diode?
3.How exactly does a transistor work,particularly the current amplification part,and what is the way to predict the values involved,viz. the forward bias voltage,collector-emitter voltage etc.
4.On the same lines,the working of various components,like Zener diode,tunnel diode,and light emitting diodes,laser diode,thyristors...the lot.
5.The explanation for Hall effect?The conventional explanation runs as follows...
"If an electric current flows through a conductor in a magnetic field, the magnetic field exerts a transverse force on the moving
charge carriers which tends to push them to one side of the conductor.A buildup of charge at the sides of the conductors will
balance this magnetic influence, producing a measurable voltage between the two sides of the conductor."
Best wishes,
Gopi.
Semiconductors
Re: Semiconductors
gopiv wrote:
In examining the elements and doping agents used in semiconductor devices, I found a distinct pattern: the base layers are typically silicon [3-2-(4)], germanium, [3-3-(4)] or tin [4-3-(4)]. Many of the compounds are lead-based, such as galena (lead sulfide, lead [4-4-(4)]. Notice the "-(4)" in every one of these base materials?
Secondly, all the doping materials are one element higher (n-type) or one element lower (p-type).
Take, for example, the original LED, gallium arsenide phosphide doped in germanium. Germanium is element #32, gallium is element #31, and arsenic is element #33. Phosphorus is element #15, but has the same electric motion as arsenic -(3). The arsenic doping is the n-type, the gallium is the p-type and the phosphorus is also n-type, and is the actual source of the visible light.
There is something "special" about this particular elemental range, with the electric displacement of (4). I suspect that Larson's notations of the intermediate and upper element ranges in the Periodic Table are not representive of the actual atomic structure.
gopiv wrote:
Where the p and n materials come into contact at the junction, a very slight potential difference occurs (as when any two dissimilar metals come into contact). With a potential difference, a tiny electric field is created to normalize the difference. When the diode is forward biased, the high voltage (relatively speaking) eliminates the electric field, and electrons pass thru the germanium as though that tiny electric field wasn't there. However, when reverse-biased, the depletion of electrons from the n-type material, and the introduction to the p-type causes the electric field to expand many thousand-fold, literally blocking electrons from crossing the junction (electrons being repeled by the electric field). Thus, in application diodes only allow current to flow in one direction.
gopiv wrote:
I have read thru about 5 descriptions on how transistors are supposed to work, with the exchanging of majority and minority carriers, but can't make any sense out of it. I suspect that they work by the base controlling the ratio of space and time in the junction -- more space (less time), electrons are blocked from flowing emitter-to-collector, more time (less space) the flow thru easily.
I suspect it might be a capacitive-type effect (in the Larsonian sense), with the base layer controlling the breakdown on the capacitive function between the emitter and collector layers. I'll post more as I come to understand it better.
gopiv wrote:
Tunneling effects are very interesting, however, and might yield a better clue as to how atomic energy levels work, since the tunnel effect is basically controlling the positioning of the quantum gap between the valence energy levels and the conduction energy level. Diodes "tunnel" when the valence level of one material overlaps the conduction level in another.
gopiv wrote:
If anyone has a good understanding of how this "conduction band" theory works, in an RS sense, please feel free to post your ideas.
I spent the last couple days researching the history of semiconductors, and came to the conclusion that legacy science doesn't have a clue as to how they actually work. Of course, they are looking at it from a "charge" perspective, not an "electron" perspective, so they have to work with positive and negative charges in balance, which account for the "majority" and "minority" carries in the various substrates.1.What are the properties of semiconductors in general,with respect to their time motion pattern?
In examining the elements and doping agents used in semiconductor devices, I found a distinct pattern: the base layers are typically silicon [3-2-(4)], germanium, [3-3-(4)] or tin [4-3-(4)]. Many of the compounds are lead-based, such as galena (lead sulfide, lead [4-4-(4)]. Notice the "-(4)" in every one of these base materials?
Secondly, all the doping materials are one element higher (n-type) or one element lower (p-type).
Take, for example, the original LED, gallium arsenide phosphide doped in germanium. Germanium is element #32, gallium is element #31, and arsenic is element #33. Phosphorus is element #15, but has the same electric motion as arsenic -(3). The arsenic doping is the n-type, the gallium is the p-type and the phosphorus is also n-type, and is the actual source of the visible light.
There is something "special" about this particular elemental range, with the electric displacement of (4). I suspect that Larson's notations of the intermediate and upper element ranges in the Periodic Table are not representive of the actual atomic structure.
gopiv wrote:
My best guess is that the n-type doping material adds additional "time" to the base material, allowing more electron capture. The p-type doping material does the opposite, reducing the overall amount of "time" in the base material, with fewer electrons (quantity-wise, we are talking ONE extra/omitted electron per million atoms).2. What is the mechanism of operation of a diode?
Where the p and n materials come into contact at the junction, a very slight potential difference occurs (as when any two dissimilar metals come into contact). With a potential difference, a tiny electric field is created to normalize the difference. When the diode is forward biased, the high voltage (relatively speaking) eliminates the electric field, and electrons pass thru the germanium as though that tiny electric field wasn't there. However, when reverse-biased, the depletion of electrons from the n-type material, and the introduction to the p-type causes the electric field to expand many thousand-fold, literally blocking electrons from crossing the junction (electrons being repeled by the electric field). Thus, in application diodes only allow current to flow in one direction.
gopiv wrote:
Still analyzing this. The transistor looks like two diodes, back-to-back, with the base at the center. The primary difference is that the base layer is very lightly doped, and very thin/small, as compared to the emitter and collector layers, which are heavily doped.3.How exactly does a transistor work,particularly the current amplification part,and what is the way to predict the values involved,viz. the forward bias voltage,collector-emitter voltage etc.
I have read thru about 5 descriptions on how transistors are supposed to work, with the exchanging of majority and minority carriers, but can't make any sense out of it. I suspect that they work by the base controlling the ratio of space and time in the junction -- more space (less time), electrons are blocked from flowing emitter-to-collector, more time (less space) the flow thru easily.
I suspect it might be a capacitive-type effect (in the Larsonian sense), with the base layer controlling the breakdown on the capacitive function between the emitter and collector layers. I'll post more as I come to understand it better.
gopiv wrote:
All these functions are variants of the basic diode, elements used to dope, and the ratio of doping levels.4.On the same lines,the working of various components,like Zener diode,tunnel diode,and light emitting diodes,laser diode,thyristors...the lot.
Tunneling effects are very interesting, however, and might yield a better clue as to how atomic energy levels work, since the tunnel effect is basically controlling the positioning of the quantum gap between the valence energy levels and the conduction energy level. Diodes "tunnel" when the valence level of one material overlaps the conduction level in another.
gopiv wrote:
I haven't had the opportunity to check into this in detail yet. Need to figure out the whole insulator / semiconductor / conductor setup yet, since the situation changes radically from a single atom, to atoms in a compound or aggregate. The former has discrete "bands", while the latter moves to a condition of chaos around a strange attractor defining the band.5.The explanation for Hall effect?
If anyone has a good understanding of how this "conduction band" theory works, in an RS sense, please feel free to post your ideas.
Every dogma has its day...