# semiconductor devices

1. ### I Pinch-Off region of MOS-FET in punch-through?

Summary: I am trying to understand the pinch-off-region of an NMOS qualitatively as NPN-structure in punch-through I was always having trouble understanding what is going on in the pinch-off region of a MOS (say NMOS) Transistor. Now I recently figured out, that this could be described (at...
2. ### Why is the band gap in alloys such as GaAs less?

In pure crystals,such as,in silicon and germanium,the band gap is more than that in compound semiconductors,such as,GaAs.Why is that so.
3. ### Doping semiconductors compounded from various element groups

Hi all - This is pulled from a past paper - 1. Homework Statement I'm only going to state the components that I find challenging of this problem - The rest will be attached in my solution set. Essentially - given an intrinsic semiconductor comprised of group II-VI elements. Upon doping with...
4. ### Engineering Computing resistance in given circuit with BJT

Hi, before you proceed with reading this question, I would like you to know what I do not expect anyone to solve this task for me. I have a problem with a single step in the solution and I'm only asking you to help me with this one step. 1. Homework Statement Compute $R_B$ so that Q-point of...
5. ### Programs Change of Major from Mechanical Engineering to Material Science

Hello guys, I recieved an admit to grad school for Mechanical Engineering, where my focus was initially Thermo-Fluids . I've also enquired about the Material Science department at the University(in the USA), and they are willing to let me transfer to the Material Science department provided I...
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### Solar Cell Problem(semiconductor)

1. Homework Statement 2. Homework Equations Voc=kt/q x ln(tpXGlXNd/(ni)2) Isc=A x q x Lp x Gl Lp=√(Dp×tp) FF=Pma/(Isc*Voc) 3. The Attempt at a Solution I got Voc=.298 V and Isc=3.04 mA I]However, I am confused as to how to find the fill factor. I know it is the maximum voltage and...
7. A

### I What is the main role of doping in a solar cell?

Is doping only to form an electric field in depletion region? Somehow I'm confused as far as I'm reading right now, the doping-generated carrier never discussed its role in the solar cell (other than leaving the ion and causing an electric field). Is not the number of carriers generated by...
8. ### I Concentration of R-G centers in a PN junction

Hey guys, Currently taking a semiconductor device fundamentals course and we are learning about R-G currents in the depletion region of a PN junction. Usually we just consider R-G centers as impurities to be avoided in the operation of a standard rectifying diode. However, I was curious as to...
9. ### I-V characteristics of a diode

I was doing an experiment to plot the IV characteristics of a diode. I connected a resistor, diode and milli ammeter in series. I connected a voltmeter across the diode. I measured the diode voltage and diode current. When i changed the resistor, I got a different set of diode voltage readings...
10. ### I How to get plot (optical gain of GaAs)?

How can i calculate this plot (photon energy dependence of the optical gain (or loss = negative gain) of GaAs with the injected carrier density as a parameter? Show calculated plot based on this equation Given parameter: mc=0.067 me; (effective mass of electrons in conduction band) mv=0.48...
11. ### Need Help to Calibrate Semiconductor Parameter Anlyzer 4156B

Hi, I have been using Semiconductor Parameter Analyzer Agilent 4156B for 1 year. Since a month it is malfuntioning. I am not getting the required IV for my Resistive Random Access Memory (RRAM) devices. To confirm, I checked my devices using some other lab's analyzer which proved that there is...
12. ### Maximum Built-In Voltage of a PN junction

Hi, I'm familiar with the expression for calculating the built-in voltage of a p-n junction. How can I find the maximum built-in voltage before the semiconductor becomes degenerate (i.e., a bad metal) if I only know the material and the intrinsic carrier concentration at a given temperature...
13. ### KVL loop in BJT biasing

Please help how Ve is calculated what i think is that it should be: -Ve=-Vee+IeRe; How Ve is taken positive please someone draw equivalent circuit for same
14. ### Semiconductor Sub-band Occupancy

1. Homework Statement a) A quantum well contains electrons at a sheet carrier density of n_s =2 \times 10^{16}m^{-2}. The electron effective mass is 0.1m_e^*. Calculate the Fermi energy of the carrier distribution in the well. You may assume the spacings between sub-bands in the quantum well is...
15. ### Silicon npn transistor

1. Homework Statement we look at a silicum n++ p+ n transistor. given: NE= 1,0×1018 cm–3; NB= 2,0×1016 cm–3; NC = 2,0×1015 cm–3; here E stands for the emitter, B for the basis and C for the collector 2. Homework Equations a. calculate the distance in eV from the fermi-level to EFi for...
16. ### Engineering Semiconductor Process Engineer Interview Questions that I may get asked

What are the commonly asked questions for the semiconductor process engineer position ? I am assuming cleanroom equipment working principles.. what else? Thanks in advance for your responses.
17. ### Engineering Solid State Physics vs Electronics Engineering

Forgive me for asking this question if the answer is obvious. The truth is I have a BENG in electrical engineering and want to know the differences between the two. From an engineer's perspective its about knowing what you can do with the devices in a useful way and design, analyze and build the...
18. ### Bipolar and unipolar voltages and their significance

Hello all! I'd like to clarify on the the differences of bipolar and unipolar voltages. I do understand that they both are used to trigger a number of semiconductor devices. Please and thank you!!