25 Questions
What is a characteristic of the energy levels of electrons in the atomic structure of an isolated atom?
They exist only at specific discrete levels
What can be inferred from the quantization of energy levels in an isolated atom?
Only specific energy levels are allowed
What is a consequence of the discrete energy levels in an isolated atom?
Electrons occupy specific energy levels
What is a characteristic of the atomic structure of an isolated atom?
Energy levels are discrete and specific
What is true about the energy levels of electrons in an isolated atom?
They exist at specific discrete levels
What type of impurity elements are used to create an n-type material?
Pentavalent impurities
Which of the following elements is NOT used to create an n-type material?
Carbon
What is the effect of introducing pentavalent impurities in a silicon base?
Creation of free electrons
According to Fig. 1.7, what is the base material used for creating an n-type material?
Silicon
What is the number of valence electrons in pentavalent impurities?
5
Which of the following semiconductor materials has the highest bandgap energy?
GaAs
Which semiconductor material has the highest electron mobility?
GaAs
Which of the following semiconductor materials has the lowest thermal conductivity?
Ge
Which semiconductor material is most commonly used in high-power, high-frequency devices?
GaAs
Which of the following semiconductor materials has the highest hole mobility?
Ge
What is the characteristic of single-crystal semiconductors?
Having a repetitive crystal structure
What is the common characteristic of gallium arsenide (GaAs), cadmium sulfide (CdS), and gallium nitride (GaN)?
They are constructed of two or more semiconductor materials
What is the type of bonding that occurs in semiconductor materials?
Covalent bonding
What is the fundamental component of an atom that has a positive charge?
Proton
What is the term for materials that are free from impurities?
Intrinsic materials
What is the minimum voltage required for the diode to turn on?
0.7 V
What is the state of the diode when vi is less than 0.7 V?
Open-circuit state
What is the output voltage when the diode is in an open-circuit state?
0 V
What happens to the diode when the input voltage is increased beyond 0.7 V?
It begins to conduct current
What is the purpose of the 0.7 V threshold voltage in a diode?
To act as a switch in a circuit
Study Notes
Semiconductor Materials
- Single-crystal semiconductors have a repetitive crystal structure, examples include germanium (Ge) and silicon (Si).
- Compound semiconductors are constructed of two or more semiconductor materials of different atomic structures, examples include gallium arsenide (GaAs), cadmium sulfide (CdS), gallium nitride (GaN), and gallium arsenide phosphide (GaAsP).
Atomic Structure
- The fundamental components of an atom are the electron, proton, and neutron.
- Electrons in an isolated atom can only exist at specific energy levels.
Doping and Semiconductor Materials
- n-Type material is created by introducing impurity elements with five valence electrons (pentavalent), such as antimony, arsenic, and phosphorus.
- The effect of these impurity elements is to introduce excess electrons, increasing the material's conductivity.
Diode Characteristics
- A diode requires a minimum applied signal of 0.7 V to turn "on" and allow current to flow.
- If the applied signal is less than 0.7 V, the diode remains in an open-circuit state and the output voltage is 0 V.
This quiz covers the basics of semiconductor materials, including their structures and properties, as well as covalent bonding and intrinsic materials.
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