Most generally a class of materials that are neither insulators or conductors in their natural state but which can be manipulated via doping or electric fields to change the conduction state. Silicon, Germanium, GaAs are some usual materials. The term is also used to speak about devices that are ...

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1answer
18 views

Relationship between band gap and built in potential for PN Junction Diode in equilibrium?

I wanted to know the relationship between the band gap (Eg) of the p/n regions in a diode and the built in potential in equilibrium. My intuition says that Eg = e*Vo. I did a small calculation for ...
0
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0answers
11 views

Fermi Level: chemical potential vs. electrochemical potential

In solid-state physics it is understood that the Fermi-Level is the electrochemical potential. The Fermi-Level is defined to: However, in thermodynamics this formula is referred to as the chemical ...
0
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0answers
17 views

Finding fermi level for germanium Semiconductor

I need to find the Fermi level of undoped and doped germanium semiconductor. The only values that i have are the ones in the pic below and that the doping concentration of acceptors is 10^17 cm^(-3): ...
0
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1answer
27 views

MOSFET Ltspice determine some parameters

I am working on project for flyback converter using Ltspice. Indeed, I have to insert the parameters for MOSFET inside the model but I have faced some difficulties to get the values from datasheet for ...
0
votes
0answers
63 views

Why forming gas contains nitrogen? [closed]

I know that forming gas anneal leads to passivation of dangling bond on SiO2/Si interface. Forming gas contains 95% of nitrogen and 5% of hydrogen. Why not 100% of hydrogen. I heard that nitrogen is ...
0
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0answers
25 views

current density vs voltage curve in OLED

What is a current density vs voltage curve? what could be an ideal white organic LED's plot? Can someone explain how to understand a J-V sweep?
0
votes
1answer
65 views

How does a junction-less transistors work?

I have recently read in a book that in 2010,junction-less transistors were developed. I can't understand how a junction-less transistor can be used to amplify current or voltage with having any ...
3
votes
3answers
689 views

Is there a fundamental limitation on how rapidly (with voltage) can a diode ’switch’ ? If so, can you pinpoint its origin?

Is there a fundamental limitation on how rapidly (with voltage) can a diode ’switch’ ? If so, can you pinpoint its origin? The diode here is a 1N914
1
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1answer
66 views

How does an IV curve of a bulk semiconductor look like?

What would an IV curve of a bulk semiconductor (i-type/n-type/p-type) look like if I do a typical voltage sweep?
0
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3answers
155 views

How exactly does a transistor amplify the input current in CE configuration

I have gone through tons of forum discussions and videos and books but they all explain in terms of mathematical equations that factor the input by a 'larger than 1' number. What happens physically ...
11
votes
3answers
740 views

Why does the intensity of light in LEDs not increase with current after a particular value?

I read in books that light intensity from an LED does not increase beyond a certain value of current. The amount of light emitted depends on the combination of holes and electrons. If so, then as the ...
2
votes
2answers
77 views

Thermal Runaway in Diodes

Datasheet for 1N5406 diode states "3.0 ampere operation at Ta = 75°C with no thermal runaway". What does this mean exactly? Can I place these in parallel to increase current capability?
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0answers
43 views

JFET - Pinch off voltage value

I have a JFET channel N and I have N_A, N_D, V_TH and the width of the channel without any bias voltage applied. I need to know the cut-off voltage. The cut-off voltage is the pinch-off voltage, ...
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votes
3answers
176 views

Why does a BJT act as an amplifier in the linear region?

I'm covering BJT's in my semiconductor class and in lecture, the professor said that BJTs are used as amplifiers in the linear region. I'm confused because I thought the gain was proportional to the ...
4
votes
4answers
617 views

Do LED have an unproductive base power consumption like incandescent bulbs?

To generate light from an incandescent body, like a tungsten filament, the body needs to be heated up to a temperature minimum needed to emmit light from that material. Up to that minimum ...
1
vote
3answers
102 views

How is a semiconductor electrically neutral?

I'm in the process of learning how transistors works, which starts with understanding how doping is used to create n-type and p-type semiconductor materials. All the resources I've read sort of ...
0
votes
0answers
59 views

Need help identifying a component

I'm doing a repair job on a hard drive logic board which has a blown component. I'm used to dealing with SATA drives where the TVS diodes have suffered damage and therefore taking them out of line / ...
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votes
1answer
70 views

Which Material is used for High Speed Devices Germanium or Silicon & Why?

Actually i am get confused with electron mobility & it's role in deciding a material for Some particular application.
0
votes
2answers
57 views

Using a single inverter to turn a light off

I'm planning on adding two strips of LED lights to the edge of my headlight enclosure. This is obviously an aesthetic "mod" however I'd like it to be semi useful as well. I'd like to be able to wire ...
0
votes
0answers
36 views

Diode at reverse biasing

Why the electrons don't move that way : giving that : 1- if the electrons of n type managed to get to p type and electric field will help them circulate again as electrons flow against electric ...
1
vote
1answer
93 views

What happened to my second half cycle of my half wave rectifier?

When I'm doing a simple half-wave rectifier with the set-up as shown above (Note: Diode D2 is not connected) and connected terminal 5 and 4 with positive and negative terminal of oscilloscope, this ...
19
votes
2answers
2k views

Why are silicon wafers used in semiconductor production round?

Wafers used for making semiconductors are round -- but this wastes quite a few chips around the periphery of the wafer in the fabrication process. Wouldn't it make sense to make the wafer as a square ...
0
votes
1answer
64 views

BJT Transistor Collector Current

As seen from the question above , I'm required to calculate Ic for both cases. Why am I not able to get the answer by using the formula \$I_C = I_s e^{V_{be}/V_T}\$ ? I was only able to get the ...
0
votes
1answer
30 views

Question on uniform semiconductor doping

So my question is shown above. For sample A , I tried to substitute the value of NA into the equation for law of mass action , but I was unable to get the answer. I had to use the equation for ...
3
votes
3answers
231 views

How do holes conduct current?

I have some questions about holes in a semiconductor. When I checked the net I found holes are said to be equivalent positive charge and they say because the hole moves from one place to another when ...
0
votes
1answer
100 views

Why diodes are made up with semiconductor?

I am little bit confuse about 'Why diodes are made of semiconductors'. I know the properties of semiconductor and also know the process of doping but still confuse to get the answer. Why the making of ...
0
votes
1answer
37 views

How does cold weather affect the electronics

At Why exactly do chips start malfunctioning once they overheat? Sharptooth asked a very nice question about how does overheat affect electronics. That raised me the question of what does cold ...
0
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2answers
50 views

Bistable circuts based on non-linear effects (like breakdown)?

Is there any known bistable circuits, which utilize parts in non-conventional mode, so that circuit is somewhat simpler than Bistable Multivibrator? Something like non-destructive breakdown of PN ...
5
votes
2answers
580 views

Gold coated pads

Is there any difference between a gold coated pad and a gold pad? I have been ordering boards from OSH park, they are really good quality, I'm just wondering what benefits this has over silver or bare ...
0
votes
4answers
116 views

Diffusion process in p-n junction

While studying about Semiconductors I couldn't get why "Negative charge stop electrons from further diffusion and Positive charge stop holes from further diffusion" as stated in (p.6) of the ...
1
vote
2answers
117 views

Dark current of photodiode gets higher after heating, why?

I'm doing some experiments using photodiodes. I raised the temperature to about 1000 degree Celsius for 1 second with melting AuSn near the PIN junction. Then the dark current of photodiode is higher ...
0
votes
1answer
66 views

Finding depletion region without built in potential

I am trying to solve a problem as to find the depletion region's width of a p+-n-n diode. I am given the width of the first n region and the doping of both n regions. Here is the problem: I ...
0
votes
0answers
52 views

Cannot find built in potential for this problem

I am doing some homework for my semiconductor physics class but cannot for the life of me find out how to continue... Here is the problem: A p+ n junction is formed in an n-type substrate with ND = ...
3
votes
5answers
195 views

Why do we need transforms (Fourier, Laplace, Z and wavelet etc.) for a signal to analyse?

Why do we need transforms (Fourier, Laplace, Z and wavelet etc.) for a signal to analyse? Is it necessary for practical calculations and analysis?
0
votes
0answers
232 views

Charge carrier concentration - intrinsic and extrinsic semiconductors

We define the charge carrier concentration in intrinsic semiconductors as: $$n^2_i = n_h \times n_e$$ In intrinsic semiconductors we say that these will be equal in number, and hence $$n_i = n_h = ...
2
votes
2answers
446 views

Making transistors or semiconductors at home

The transistor was invented some 50 65 years ago, so is it not about time to be able to make transistors or other semiconductors at home? Would that be possible?
3
votes
1answer
104 views

Metal semiconductor contacts

I’m headed back to the CNF (http://www.cnf.cornell.edu/) shortly. It’s a user clean room facility for semiconductor processing. My goal is to make some very simple samples, for use in student teaching ...
1
vote
1answer
81 views

Why does it take several seconds of time for the photodiodes to come out of saturation?

I am currently studying about photodiodes and came across this fact that photodiodes take quite a bit of time to come out of the saturation. What really happens during this time (after it is saturated ...
0
votes
3answers
165 views

How to remove energy from inductor using semiconductors?

So I have this coil and I'm driving dc current through it. This coil has inductance and thus stores energy from the dc current. I have to remove this energy before I can change the polarity of my ...
1
vote
1answer
334 views

How to build an H-bridge using MOSFETs? [duplicate]

I want to reverse the polarity of my current source, which is a capacitor in this case, in the middle of discharging phase. Also the capacitor bank is being discharged through a coil to make a short ...
0
votes
1answer
95 views

What happens on heating an intrinsic semiconductor?

Suppose I have an intrinsic semiconductor and I heat it up on one side. What will be the changes that will occur? As far as I know it won't become an extrinsic semiconductor because that would need to ...
2
votes
3answers
923 views

Transistors why does increasing base current increase collector current?

I am new to this area so please can you keep your answers simple, thanks. From what I know for an npn transistor in the common-emitter connection the base-emitter junction is in the forward bias and ...
0
votes
2answers
144 views

Can (CPU) logic and (flash) memory be located on the same die?

Is it possible to manufacture semiconductors in a way that places logic (for example, a CPU core) on the same die with non-volatile flash (or other EEPROM memory) circuits? What about DRAM? It ...
2
votes
1answer
266 views

If the depletion layer of a transistor collector/base junction is thick, why are majority carriers still collected?

In "Principles of transistor circuits, 8th edition" (top of p26) it is said that once holes have been injected in the base region by a forward biased base-emitter junction (which I understand) of a ...
0
votes
0answers
29 views

Find the Output curve for the given Input Curve

For the circuit given below find the output wave form for the given input wave. The following are the answer choices for the curve of Vout. The answer choice selected in my book is (3) Please ...
0
votes
1answer
42 views

Why is the voltage across a PN junction 0 v when it is in open circuit conditions? [duplicate]

Why is the voltage across a PN junction 0 v when it is in open circuit conditions ?
0
votes
1answer
228 views

Cutoff and Conducting diodes

Why is D1 considered cutoff and D2 considered conducting ? Note : I am working with constant voltage model where the diode voltage is 0.7v and I need to figure out I and V. Please explain why D1 is ...
0
votes
3answers
166 views

Instructions on how to build electronic devices [duplicate]

I have got plenty of books in the theory of electronic devices, but I wish to build these transistors (BJT, MOSFETS, etc) and diodes by myself. Which books are there in offer to learn how to do this? ...
1
vote
1answer
545 views

Why can current flow through the reverse biased base-collector junction (N-P junction) in a BJT with a forward biased base-emitter junction?

If the base-emitter junction of a BJT is forward biased, then current can flow through the reverse biased base-collector junction (N-P junction). This disagrees with my understanding of the PN ...
2
votes
3answers
102 views

reason for degradation of photovoltaics

Photovoltaic panels can have 20 or 25 year underwritten warranties with a guaranteed remaining efficiency of 80 % of the new panel. That means, that photovoltaic panels seem to degrade somehow. Why ...