Photonic Devices and Photo Detectors

A photodiode converts light into an electrical current or voltage.

The response time of a photodiode decreases as its surface area increases.

A photodiode converts light to electricity, while an LED converts electricity to light.

<p>The two types of current generated are <strong>photocurrent</strong> and <strong>dark current</strong>.</p> Signup and view all the answers

<p>A junction photodiode consists of a pn junction, formed by a p-type semiconductor material like phosphorous embedded in a clear plastic medium.</p> Signup and view all the answers

<p>A junction photodiode operates under reverse bias, where light exposure causes a change in current proportional to the light flux.</p> Signup and view all the answers

<p>The intrinsic region in a PIN photodiode acts as a <strong>wide depletion region</strong> when reverse biased, allowing for efficient light absorption and generation of electron-hole pairs.</p> Signup and view all the answers

<p>A wider depletion region increases the sensitivity of a photodiode.</p> Signup and view all the answers

<p>Some types of photodiodes include PN photodiodes, Schottky photodiodes, PIN photodiodes, and Avalanche photodiodes.</p> Signup and view all the answers

<p>A faster response time allows the photodiode to detect and respond to rapid changes in light intensity, making it suitable for applications like high-speed data transmission.</p> Signup and view all the answers

<p>One way to improve sensitivity is to <strong>increase the width of the depletion region</strong>.</p> Signup and view all the answers

<p>A PIN photodiode has an <strong>intrinsic region</strong> between the p and n regions, which is <strong>lightly doped and wide</strong>.</p> Signup and view all the answers

<p>The clear plastic medium allows light to reach the delicate pn junction inside the photodiode, facilitating efficient light detection.</p> Signup and view all the answers

<p>Photodiodes are used in <strong>smoke detectors, compact disc players, and remote controls.</strong></p> Signup and view all the answers

<p>PIN photodiodes have a <strong>higher sensitivity</strong> due to their wider depletion region.</p> Signup and view all the answers

<p>Minimizing dark current is crucial because it <strong>reduces noise</strong> in the signal, enhancing the ability to detect weak light signals.</p> Signup and view all the answers

<p>Photonic devices offer advantages like higher speed of information transmission, the ability to travel long distances within a short time, and greater immunity to electromagnetic interference.</p> Signup and view all the answers

<p>A photodetector converts incident light signals into an electrical voltage or current. This conversion occurs when light hits the junction of the photodetector, generating electrons and holes that contribute to the electrical signal.</p> Signup and view all the answers

<p>SSL utilizes light-emitting diodes (LEDs) as the primary light source. It offers superior energy efficiency, longer lifespan, reduced heat generation, and environmentally friendly technology compared to conventional lighting technologies.</p> Signup and view all the answers

<p>Three essential requirements for an effective photodetector include high sensitivity, high reliability, and a short response time.</p> Signup and view all the answers

<p>Applications of photonic technology include telecommunications, data processing and transportation, medicine and biotechnologies, and lighting.</p> Signup and view all the answers

<p>In photonic devices, photons act as carriers of information, analogous to the role of electrons in electronic devices. However, photons travel at the speed of light, providing a significant speed advantage.</p> Signup and view all the answers

<p>Optical fibers allow efficient transmission of light over long distances with minimal signal loss due to their ability to confine light within their core through total internal reflection.</p> Signup and view all the answers

<p>Solar cells convert light energy into electrical energy. They share a similar principle of operation with photodetectors, as both devices absorb light and generate an electrical signal.</p> Signup and view all the answers

<p>The antireflection coating reduces the amount of light that is reflected back from the surface of the photodiode, increasing the amount of light that is absorbed and converted into electrical current.</p> Signup and view all the answers

<p>The depletion region is formed by the diffusion of lightly doped p-type material into a heavily doped n-type material. This diffusion creates a region where there are no free charge carriers, leading to a depletion of charge.</p> Signup and view all the answers

<p>The active area is coated with an antireflection coating and is designed to absorb light and generate current. The non-active area is coated with a thick layer of SiO₂ to prevent the photodiode from responding to light that falls on this area.</p> Signup and view all the answers

<p>Minority carriers, such as electrons in the p-type region and holes in the n-type region, are thermally generated and contribute to the reverse saturation current by moving across the junction. This current flows even in the absence of incident light.</p> Signup and view all the answers

<p>The depletion region has a strong electric field that attracts the photogenerated electrons and holes to opposite sides of the junction, thus creating a current flow. The electric field helps separate the carriers and prevents them from recombining.</p> Signup and view all the answers

<p>Reverse bias creates a strong electric field in the depletion region, which is necessary to separate the photogenerated electron-hole pairs and collect them as current. Without reverse bias, the photodiode would not be able to effectively detect light.</p> Signup and view all the answers

<p>A thicker non-active area reduces the overall sensitive area, slowing down the response time as it takes longer for light to reach the active area. However, it also reduces the leakage current and improves the overall sensitivity of the photodiode.</p> Signup and view all the answers

<p>Higher doping levels in the n-type region lead to a wider depletion region which increases the internal electric field for better charge separation and faster response time. However, it decreases the overall sensitivity. Conversely, lower doping levels lead to lower response speeds but higher sensitivity.</p> Signup and view all the answers

A light detector that converts light into current or voltage.

A light-emitting diode that converts current into light.

A basic type of photodiode formed by p-type and n-type semiconductor materials.

A type of photodiode that uses a metal-semiconductor junction for faster response.

A photodiode that has an intrinsic layer between p-type and n-type material.

A photodiode that operates with a high reverse bias to create an avalanche effect, increasing sensitivity.

A photodiode formed by a reverse-biased pn junction in clear plastic.

The speed at which a photodiode detects light and converts it to current.

The branch of science dealing with the production and detection of photons.

Devices that utilize photons for various applications like communication and lighting.

Lighting technology using mainly light emitting diodes (LEDs) for higher efficiency.

A device that converts light signals into voltage or current, crucial in optical communications.

A type of photodetector that amplifies light signals into electrical signals.

Devices that absorb light to convert it into electrical energy, similar to photodetectors.

Part of the photodiode that responds to light.

Area between p-type and n-type regions in a photodiode.

Current that flows in reverse bias; due to minority carriers.

Charge carriers that are present in lesser amounts in a semiconductor.

Process where light energy excites electrons, releasing them.

Result of photon absorption; an electron plus a hole.

Layer that minimizes reflection to enhance light absorption.

Part of the photodiode that does not convert light into current.

Electron-hole pairs created in a photodiode when exposed to light.

The current generated by the movement of photo carriers in a photodiode.

Current that flows through a photodiode even in the absence of light.

Used in devices like smoke detectors, TVs, and medical instruments.

The lightly doped semiconductor region between p and n layers in a PIN photodiode.

Area in a diode where electric field effects separate charge carriers.

The process where light energy promotes electrons from the valence to the conduction band.