# A Ga As device is doped with a donor concentration of 3*1010cm-3.For the device to operate properly, the intrinsic carrier concentration must remain less than 5% of the total concentration. The maximum temperature on which the device may operate is

1.  763K

2.  942K

3.  486K

4.  243K

4

763K

Explanation :
No Explanation available for this question

# A silicon crystal having a cross sectional area of 0.001cm2 and a length of 20μm is connected to its ends to a 20v battery.At T=300K,we want a current of 100 mA in crystal.The concentration of donor atoms to be added is

1.  2.4*1013cm-3

2.  4.6*1013cm-3

3.  7.8*1014cm-3

4.  8.4*1014cm-3

4

4.6*1013cm-3

Explanation :
No Explanation available for this question

# An n-type silicon sample has a resistivity of 5 Ω-cm at T= 300K.If mobility is μn=1350 cm2/V-s, then donor impurity concentration is

1.  2.86*10-14cm-3

2.  9.25*1014cm-3

3.  11.46*1015cm-3

4.  1.1*10-15cm-3

4

9.25*1014cm-3

Explanation :
No Explanation available for this question

# For a particular semiconductor material following parameters are observed : μn=1000cm2/V-s μp=600cm2/V-s Nc= Nv=1019cm-3 These parameters are independent of temperature. The measured conductivity of the intrinsic material is σ=10-6(Ω-cm)-1 at T=300K The conductivity at T=500K is

1.  2*10-4(Ω-cm)-1

2.  4*10-5(Ω-cm)-1

3.  2*10-5(Ω-cm)-1

4.  6*10-3(Ω-cm)-1

4

6*10-3(Ω-cm)-1

Explanation :
No Explanation available for this question

# In a particular semiconductor the donor inpurity concentration is Nd=1014cm-3.Assume the following parameters μn=1000cm2/V-s Ne=2*1019(T/3000)3/2cm-3 Nv=1*1019(T/3000)3/2cm-3 Eg=1.1eV If an electric field of E=100V/cm is appiled, then electric current density at 300K is

1.  2.3A/cm2

2.  1.6 A/cm2

3.  9.6 A/cm2

4.  3.4 A/cm2

4

1.6 A/cm2

Explanation :
No Explanation available for this question

# When conductivity is minimum, then whole concentration is

1.  7.2*1011cm-3

2.  1.8*1013cm-3

3.  1.44*1011cm-3

4.  9*1011cm-3

4

1.8*1013cm-3

Explanation :
No Explanation available for this question

# Three scattering mechanism exist in a semiconductor. If only first mechanism were present,then mobility would be 750cm2/V-s.If only third mechanism were present, then mobility would be 1500 cm2/V-s.The net mobility is

1.  2750 cm2/V-s

2.  1114 cm2/V-s

3.  818 cm2/V-s

4.  250 cm2/V-s

4

250 cm2/V-s

Explanation :
No Explanation available for this question

# Expression for the output voltage V0 in terms of the input voltage V1 and V2 in the circuit shown in the figure, assuming operational amplifier to be ideal is V0=A1V1+A2V2 values of A1 and A2 would be respectively

1.  9 and -10

2.  -9 and 10

3.  9.9 and -10

4.   -9.9 and 10

4

-9 and 10

Explanation :
No Explanation available for this question

# A sample of N-type semiconductor has electron density of 6.25*1018/cm3 at 300K.If the intrinsic concentration of carriers in this sample is 2.25*1013/cm3, at this temperature, the hole density works out to be

1.  104/cm3

2.  104/cm3

3.  1010/cm3

4.  1012/cm3

4

104/cm3

Explanation :
No Explanation available for this question

1.  20A/cm2

2.  16A/cm2

3.  24A/cm2

4.  30A/cm2

4