Question

The emission of electrons from the host atoms due to the high electric field is known as (A) avalanche field emission (B) Breakdown field emission (C) zener field emission (D) internal field emission

Short answer

The correct term for the phenomenon of emitting electrons from host atoms due to a high electric field is (B) Breakdown Field Emission. It leads to a rapid breakdown of the material's insulating properties and increased electrical conductivity.

Step-by-step solution

Understanding Avalanche Field Emission

Avalanche field emission occurs when there is a high electric field in a material that causes free electrons to gain enough energy to produce more free electrons through collisions with host atoms. This creates an exponential increase or "avalanche" in the number of free electrons, leading to a sudden and often catastrophic breakdown of the insulating properties of the material.

Understanding Breakdown Field Emission

Breakdown field emission refers to the phenomenon where the electric field in a material becomes sufficiently high to cause a rapid breakdown of the insulating properties of the material, leading to the release of electrons from host atoms and a sudden increase in electrical conductivity.

Understanding Zener Field Emission

Zener field emission, also known as Zener breakdown, is a process that can occur in semiconductors under the influence of a high electric field. Similar to avalanche field emission, electrons are accelerated through collisions with host atoms, resulting in the generation of more free electrons. However, in Zener breakdown, the energy gained by the electrons comes from the strong electric field, rather than from thermal energy.

Understanding Internal Field Emission

Internal field emission, or internal photoemission, is the process by which electrons overcome the energy barriers existing between different materials or layers of a device, such as a metal-semiconductor or insulator-semiconductor interface, due to the presence of electric fields.

Identifying the Correct Term

From the provided options, it is clear that the correct term for the emission of electrons from the host atoms due to the high electric field is (B) Breakdown Field Emission. This process causes a rapid breakdown of the insulating properties of the material, leading to the release of electrons from host atoms and increased electrical conductivity.

Key concepts

Avalanche Field Emission

Avalanche Field Emission is an intriguing phenomenon occurring within materials subjected to a high electric field. Picture electrons, initially bound to their atoms, becoming energetic enough to break free. This freed electron then collides with other atoms, knocking loose more electrons, much like a snowball rolling down a hill and collecting more snow until it becomes an avalanche. The process kicks into action when the applied electric field is so strong that it imparts enough kinetic energy to electrons, enabling them to ionize host atoms through impact.

• The newly freed electrons lead to exponential growth in the number of charge carriers.
• This surge results in a noticeable increase in electrical conductivity.
• In extreme cases, it can cause a breakdown of the material's insulating properties.

Avalanche field emission is a key mechanism in devices like avalanche photodiodes, which make use of this chain reaction to multiply weak electrical signals. Understanding this can help in designing electronic components that are both efficient and robust in managing high electric fields.

Zener Field Emission

Zener Field Emission, or Zener breakdown, is particularly relevant in the realm of semiconductors. It is akin to avalanche field emission but with a twist: the electrons here gain their energy not through collisions alone but due to a powerful electric field that propels them across energy barriers. What unfolds is a process where electrons tunnel through the energy gap of a semiconductor, aided by the intense electric field.

• This involves an electron passing through an energy barrier without needing sufficient energy to climb over it, a quantum mechanical effect known as tunneling.
• Zener breakdown is essential in devices designed to harness stable voltage regulation, such as Zener diodes which maintain a constant voltage across them regardless of changes in current flow.
• It allows for efficient control of electrical characteristics in semiconductors under high electric fields.

Grasping the concept of Zener field emission is crucial for students and engineers working with voltage regulation and semiconductor technology.

Internal Field Emission

Internal Field Emission, also termed internal photoemission, is a process harnessed especially in modern electronic and optoelectronic structures. It describes the movement of electrons across internal boundaries of materials, particularly from a metal to a semiconductor, or from an insulator to a semiconductor interface under the influence of an electric field. The phenomenon becomes significant when an electron has enough energy to overcome the energy barriers present between two different materials or layers within a device.

• This energy can come from photons (light), causing electrons to be emitted internally between these interfaces.
• This internal movement is crucial for devices such as photodetectors and solar cells, where the conversion of light into electronic signals or electricity is required.
• Internal field emission can significantly impact the efficiency and performance of these devices.

Appreciating internal field emission opens doors to understanding the inner workings of advanced photovoltaic and optoelectronic technologies, enabling enhanced performance and innovation in energy solutions.