30 Questions
What is the expression for electrical conductivity in a semiconductor?
sigma = n/emue + p/emuh
How does the conductivity of pure silicon change with increasing temperature?
it increases
How does the conductivity of intrinsic semiconductors change with increasing temperature?
it increases
What is the relationship between the number of conduction electrons in an intrinsic semiconductor and the energy bandgap?
proportional to e^(-Egap/kT)
What is the energy bandgap of CdS in eV?
2.40
For an intrinsic semiconductor, what is the relationship between the number of electrons and the number of holes?
the number of electrons is equal to the number of holes
In an n-type semiconductor, what are the majority carriers?
Electrons
What is the relationship between the difference in electronegativity between the constituting elements and the energy bandgap in compound semiconductors?
The wider the difference, the wider the energy bandgap.
What type of bonds are formed between the impurity and the nearest Si atom when a group-V impurity is added to Si?
Covalent bonds
When a group-V impurity is added to Si, how many valence electrons from the impurity form bonds with the nearest Si atom?
5
In an intrinsic semiconductor, what is the typical state of the valence and conduction bands?
The valence band is completely filled, and the conduction band is partially filled.
What is the correct statement about phosphorus substitutional atoms in a silicon at room temperature?
They are triply ionized
What is the primary cause of free electron creation in an intrinsic conductor?
Thermal excitation
In an intrinsic semiconductor, what is the result of thermal excitation?
A free electron is created in the conduction band, and a hole is created in the valence band.
What is the correct statement about donor exhaustion in a n-type semiconductor?
It occurs when all n-type dopant atoms have donated their extra electrons to the conduction band
What type of dopant is Boron in Si and Ge semiconductors?
p-type
What is the primary mechanism of electrical conduction in intrinsic semiconductors?
Migration of electrons and holes
What type of excitation is primarily responsible for conductivity in intrinsic semiconductors?
Thermal excitation
What are the majority carriers in a p-type semiconductor?
Holes
What happens to the conductivity of doped silicon with increasing doping concentration?
It increases
In an n-type doped silicon, what do the n-type atoms donate to give the silicon a conduction band?
Electrons
What is the extrinsic doping level for phosphorus in silicon?
1E21/m^3
At what temperature is the thermal energy too low to excite donor electrons, resulting in a freeze-out?
150 K
What is the temperature range for which conduction is extrinsic in an extrinsic semiconductor?
150 K to 400 K
What is the nature of conduction in an extrinsic semiconductor at very high temperatures?
intrinsic
How can the structure of glassy silicate ceramics be modified?
by using network modifiers
What is the effect of flaws on the properties of ceramics?
they significantly affect the strength
What is the primary purpose of refractories in ceramics?
to withstand high temperatures
What is the main application of ceramic glasses?
in both optical and glass container applications
What is the classification of ceramic materials that includes glasses, clays, and refractories?
traditional ceramics
Test your knowledge of semiconductor properties, including the relationship between electronegativity and energy bandgap, and the characteristics of valence and conduction bands in intrinsic semiconductors.
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