If you want to dope GaAs to make an n-type semiconductor with an element to replace Ga, which element would you pick? a. Zn b. Al c. In or d. Si

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Understand the concept of doping: Doping is the process of adding impurities to a semiconductor to change its electrical properties. An n-type semiconductor is created by adding an element with more valence electrons than the host material.

Identify the host material: GaAs (Gallium Arsenide) is a compound semiconductor where Ga (Gallium) has 3 valence electrons and As (Arsenic) has 5 valence electrons.

Determine the type of dopant needed: To create an n-type semiconductor, you need to add an element that has more valence electrons than Ga, which has 3 valence electrons.

Evaluate the options: a. Zn (Zinc) has 2 valence electrons, b. Al (Aluminum) has 3 valence electrons, c. In (Indium) has 3 valence electrons, and d. Si (Silicon) has 4 valence electrons.

Select the appropriate element: Choose the element with more valence electrons than Ga to create an n-type semiconductor.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Doping in Semiconductors

Doping is the intentional introduction of impurities into a semiconductor to modify its electrical properties. In n-type semiconductors, elements with more valence electrons than the semiconductor material are added, providing extra electrons that enhance conductivity. For gallium arsenide (GaAs), which has three valence electrons from Ga and five from As, n-type doping typically involves elements from group V of the periodic table.

Group V Elements

Group V elements, such as phosphorus (P) and arsenic (As), have five valence electrons and are commonly used to create n-type semiconductors. When these elements replace gallium (Ga) in GaAs, they contribute an extra electron, increasing the material's electron concentration and enhancing its conductivity. Understanding the role of these elements is crucial for selecting appropriate dopants.

Element Substitution in GaAs

When substituting elements in GaAs for doping purposes, it is essential to choose elements that can effectively replace gallium while providing the desired electrical properties. Among the options given, indium (In) is a group III element like gallium, but it does not provide extra electrons. In contrast, silicon (Si) is a group IV element that can act as a donor in certain conditions, but it is less effective than group V elements for n-type doping in GaAs.

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