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 2017 Set 1
MCQ (Single Correct Answer)
+1
-0.3
A bar of Gallium Arsenide (GaAs) is doped with Silicon such that the Silicon atoms occupy Gallium and Arsenic sites in the GaAs crystal. Which one of the following statement is true?
A
Silicon atoms act as p-type dopants in Arsenic sites and n-type dopants in Gallium sites
B
Silicon atoms act as n-type dopants in Arsenic sites and p-type dopants in Gallium sites
C
Silicon atoms act as p-type dopants in Arsenic as well as Gallium sites
D
Silicon atoms act as n-type dopants in Arsenic as well as Gallium sites
4
GATE ECE 2016 Set 1
MCQ (Single Correct Answer)
+1
-0.3
A small percentage of impurity is added to an intrinsic semiconductor at 300 K. Which one of the following statements is true for the energy band diagram shown in the following figure? GATE ECE 2016 Set 1 Electronic Devices and VLSI - Semiconductor Physics Question 27 English
A
Intrinsic semiconductor doped with pentavalent atoms to form n-type semiconductor
B
Intrinsic semiconductor doped with trivalent atoms to form n-type semiconductor
C
Intrinsic semiconductor doped with pentavalent atoms to form p-type semiconductor
D
Intrinsic semiconductor doped with trivalent atoms to form p-type semiconductor
GATE ECE Subjects
EXAM MAP
Medical
NEETAIIMS
Graduate Aptitude Test in Engineering
GATE CSEGATE ECEGATE EEGATE MEGATE CEGATE PIGATE IN
Civil Services
UPSC Civil Service
Defence
NDA
Staff Selection Commission
SSC CGL Tier I
CBSE
Class 12