1
GATE ECE 2022
MCQ (Single Correct Answer)
+1
-0.33

Consider a long rectangular bar of direct bandgap p-type semiconductor. The equilibrium hole density is 1017 cm$$-$$3 and the intrinsic carrier concentration is 1010 cm$$-$$3. Electron and hole diffusion lengthss are 2 $$\mu$$m and 1 $$\mu$$m, respectively. The left side of the bar (x = 0) is uniformly illuminated with a laser having photon energy greater than the bandgap of the semiconductor. Excess electron-hole pairs are generated ONLY at x = 0 because of the laser. The steady state electron density at x = 0 is 1014 cm$$-$$3 due to laser illumination. Under these conditions and ignoring electric field, the closest approximation (among the given options) of the steady state electron density at x = 2 $$\mu$$m, is _____________.

A
0.37 $$\times$$ 1014 cm$$-$$3
B
0.63 $$\times$$ 1013 cm$$-$$3
C
3.7 $$\times$$ 1014 cm$$-$$3
D
103 cm$$-$$3
2
GATE ECE 2022
MCQ (Single Correct Answer)
+1
-0.33

In a non-degenerate bulk semiconductor with electron density n = 1016 cm$$-$$3, the value of EC $$-$$ EFn = 200 meV, where EC and EFn denote the bottom of the conduction band energy and electron Fermi level energy, respectively. Assume thermal voltage as 26 meV and the intrinsic carrier concentration is 1010 cm$$-$$3. For n = 0.5 $$\times$$ 1016 cm$$-$$3, the closest approximation of the value of (EC $$-$$ EFn), among the given options is _________.

A
226 meV
B
174 meV
C
218 meV
D
182 meV
3
GATE ECE 2022
Numerical
+1
-0.33

An ideal MOS capacitor (p-type semiconductor) is shown in the figure. The MOS capacitor is under strong inversion with VG = 2V. The corresponding inversion charge density (QIN) is 2.2 $$\mu$$C/cm2. Assume oxide capacitance per unit area as Cox = 1.7 $$\mu$$F/cm2. For VG = 4V, the value of QIN is __________ $$\mu$$C/cm2 (rounded off to one decimal place).

GATE ECE 2022 Electronic Devices and VLSI - BJT and FET Question 1 English

Your input ____
4
GATE ECE 2022
MCQ (More than One Correct Answer)
+2
-0.67

Select the CORRECT statements regarding semiconductor devices

A
Electrons and holes are of equal density in an intrinsic semiconductor at equilibrium.
B
Collector region is generally more heavily doped than Base region in a BJT.
C
Total current is spatially constant in a two terminal electronic device in dark under steady state condition.
D
Mobility of electrons always increases with temperature in Silicon beyond 300 K.
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