Name: how bias changes metal-semiconductor current
Uploaded: 2024-07-08T13:20:09.000Z
Duration: 1 min 27 s
Channel: JoVE

La polarización de uniones metálicas y semiconductoras de tipo n implica aplicar un voltaje al metal mientras se conecta a tierra el semiconductor. La corriente resultante es positiva cuando fluye del metal al semiconductor.
Para las uniones de Schottky, la aplicación de un voltaje positivo reduce el nivel de Fermi del metal, reduciendo la barrera para los electrones en el semiconductor y permitiendo el flujo neto de electrones desde el semiconductor al metal. Esto da como resultado una corriente de polarización directa que aumenta rápidamente.
Por el contrario, el voltaje negativo eleva el nivel de Fermi de los metales, bloqueando el flujo de electrones del semiconductor al metal. Sin embargo, algunos electrones superan la barrera de unión, lo que conduce a una pequeña corriente de polarización inversa.
Para uniones óhmicas, incluso un pequeño voltaje positivo desencadena una gran corriente de polarización directa debido a la ausencia de cualquier barrera. Bajo la polarización inversa, existe una pequeña barrera para el flujo de electrones desde el metal hasta el semiconductor, que desaparece si la polarización inversa supera unas pocas décimas de voltio.
El comportamiento se invierte para los contactos formados con metales y semiconductores de tipo p.
La polarización de las uniones metal-semiconductores permite controlar el flujo de corriente, que es esencial en dispositivos como diodos, transistores y células fotovoltaicas.

polarización de uniones metal-semiconductores

Polarizar uniones metal-semiconductor implica aplicar un voltaje a través de la unión. Específicamente, el metal está conectado a una fuente de voltaje, mientras que el semiconductor está conectado a tierra. Esta técnica es esencial para controlar la dirección y magnitud del flujo de corriente en dispositivos electrónicos, incluidos diodos, transistores y células fotovoltaicas.
En las uniones Schottky, donde el semiconductor es de tipo n, aplicar un voltaje positivo al metal en relación con el semiconductor reduce su nivel de Fermi. Reduce la barrera de energía que los electrones del semiconductor deben superar para pasar al metal. Esto permite un flujo significativo de electrones desde el semiconductor al metal, lo que da como resultado una corriente que aumenta rápidamente cuando la unión está polarizada directamente. Cuando se aplica un voltaje negativo, la situación se invierte. El nivel de Fermi del metal aumenta, mejorando la barrera contra el flujo de electrones desde el semiconductor al metal. A pesar de esto, unos pocos electrones pueden superar la barrera, generando una corriente de polarización inversa menor.
Las uniones óhmicas se comportan de manera diferente. Debido a la ausencia de una barrera significativa, incluso un ligero voltaje positivo puede inducir una gran corriente de polarización directa, permitiendo un fácil flujo de electrones desde el semiconductor al metal. En la polarización inversa, existe una barrera mínima para el flujo de electrones desde el metal al semiconductor, pero esta barrera desaparece efectivamente si el voltaje de polarización inversa excede unas pocas décimas de voltio.
La dinámica de interacción cambia con los semiconductores tipo p. El comportamiento descrito para semiconductores tipo n tanto en uniones Schottky como en uniones Óhmicas se invierte. Esta capacidad de manipular el flujo de corriente mediante polarización es esencial para el funcionamiento de muchos componentes electrónicos y proporciona la base para la funcionalidad de una amplia gama de dispositivos.

Polarización de uniones metal-semiconductores

La polarización de uniones metálicas y semiconductoras de tipo n implica aplicar un voltaje al metal mientras se conecta a tierra el semiconductor. La corriente resultante es positiva ...

Education

Educación

JoVE Core

Electrical Engineering

Ingeniería Eléctrica

Unit 1

Unidad 1

Basics of Semiconductors

Conceptos básicos de los semiconductores

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

Biasing of Metal-Semiconductor Junctions

how bias changes metal-semiconductor current

Biasing metal-semiconductor junctions means applying a voltage across the junction. The metal connects to the voltage source, and the semiconductor is grounded. This setup helps control the direction and size of current in devices such as diodes, transistors, and photovoltaic cells.

In a Schottky junction with an n-type semiconductor, a positive voltage on the metal lowers its Fermi level. A Fermi level is the energy level that helps describe how electrons are distributed. Lowering this level reduces the barrier electrons in the semiconductor must cross to move into the metal. As a result, many electrons flow from the semiconductor to the metal, and the current rises quickly in forward bias.

A negative voltage reverses this effect. The metal Fermi level rises, which increases the barrier for electrons moving from the semiconductor to the metal. A small reverse current can still appear because a few electrons are able to cross the barrier.

Ohmic junctions behave differently because they do not have a large barrier. Even a small positive voltage can produce a large forward current, so electrons move easily from the semiconductor to the metal. In reverse bias, there is only a small barrier for electrons moving from the metal to the semiconductor, and that barrier can disappear if the reverse voltage goes beyond a few tenths of a volt.

The behavior changes again with p-type semiconductors. In both Schottky and Ohmic junctions, the n-type behavior is reversed. This control over current flow is important for many electronic components and supports the function of a wide range of devices.

How Bias Changes Metal-Semiconductor Current

how-bias-changes-metal-semiconductor-current

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Biasing metal-semiconductor junctions means applying a voltage across the junction. The metal connects to the voltage source, and the semiconductor is grounded. This setup helps control the direction and size of current in devices such as diodes, transistors, and photovoltaic cells. In a Schottky junction with an n-type semiconductor, a positive voltage on the metal lowers its Fermi level. A Fermi level is the energy level that helps describe how electrons are distributed. Lowering this level...

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Learn how biasing changes current in Schottky and Ohmic metal-semiconductor junctions, including n-type and p-type behavior in electronics.

How Bias Changes Metal-Semiconductor Current | JoVE K12

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electrical engineering

How Bias Changes Metal-Semiconductor Current

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