Please, help explain the following concept: We know that semiconductor bandgap changes with temperature. We also know qualitatively how the doping energy level (E_D for donors and E_A for acceptors) changes with increasingdoping density. Give a qualitative description of what happens to donor energy level (E_D) as N_D increases. Whathappens to the Fermi level, E_F at very high doping density? Make comment on the Boltzmannapproximation as the doping density increases to very high concentrations. Please illustrate the aboveusing schematics (Band Diagram).

Here are some statements about a p-n junction diode. Some are TRUE and some are FALSE. i. Applying a negative bias to the p-side and a positive bias to the n-side allows a forward current flow. ii. When the p-n junction is under reverse bias, the Fermi level is continuous across the junction. iii. The forward bias current is made up of holes from the p-side and electrons from the n-side flowing across the junction. iv. Under reverse bias, you can get minority electrons flowing from the p-side to the n-side of the junction. v. To get a large built-in voltage, you need to heavily dope the p-side and n-side of the junction. vi. The built-in voltage (or contact potential) of a p-n junction is typically twice the value of the band-gap of the semiconductor. Which of the following statements is correct: (i) and (ii) are both FALSE (ii) and (v) are both FALSE (iii) and (vi) are both FALSE

Consider a silicon P- N step junction diode with Nd = 1018 cm-3 and Na = 5 × 1015 cm-3 . Assume T=300K. Calculate the capacitance when it is under reverse biased at 1.5V. Assume a cross sectional area of 1um2. If you want to make the capacitance decrease by factor of 3 what should be the width of the depletion layer?

In the case of pn junction of the same material, the internal potential Vbi increases as more doping is performed in each of the p and n regions. Explain this by drawing an energy band diagram.

Show and expalin all the steps in the derivation

a) Use the diode’s characteristic equation,ID=Is exp(VD/VT), to determine the currentsourceIso that the output voltage is 1.5 V. b) If a load is attached to the output that draws 1 mA, what is the output voltage? c) If the circuit heats up to 40◦C, what is the output voltage without a load?

10+ D NAME: The diodes in the circuit below have a saturation current Is = 10-¹4A. The NMOSFET has a threshold voltage of +1V and a K parameter of 10mA/V². > ID = Is (evo/VT - 1) a) Use the exponential diode model b) Oops. Someone built the circuit below, and apparently made a mistake selecting the components. They measure the voltage VA and it is equal to 1.9V. Based on VA = 1.9V, determine the expected value of V₂. +1 -3 V AVD -0.4 3-V 3-2V0 I VA=1.9V 041 VA to calculate VA. 2.2 ΚΩ +10V T 100 Ω NMOSFET VB Ins=4.05m

Consider an idealized diode with a reverse saturation current 0.01 mA and an abrupt turn-on voltage of 0.7 V (assume no breakdown and operation away from the knee of the diode curve). For the circuit shown, both resistors are 100 2, the constant source is Vp = 5 V, and the time-dependent source is V3 = 20 sin(at) V. Calculate (a) the peak positive voltage V and the associated current through the diode and (b) the peak negative voltage V and the associated current through the diode. Rulamting R Vs + > KHI

Diodes D1, D2, D3 and D4 are identical Silicon diodes with forward voltage drop of 0.7volts. Consider vi to be the circuit's input voltage.A) Under what input conditions will diode D1 conduct? B) If D1 is conducting, express vo in terms of vi. C) Under what conditions will diode D4 conduct? D) If D4 is conducting, express vo in terms of vi. E) Under what input conditions will none of the diodes be conducting? F) If none of the diodes are conducting, what is vo? G) The input to the circuit has the waveform shown below. Plot the waveform of thevoltage vo. Show all the important quantities in your plot.

Capacitance per unit area at no reverse bias is two pF/cm². For a step graded diode of area 5cm², what is net capacitance at 99 V reverse bias voltage?