Class: Senior Secondary School 1 (SS1, SS 1, SSS1, SSS 1)
Term: 3rd Term
Week: 10
Age: 15 years
Duration: 45 minutes
Subject: Basic Electronics
Curriculum Theme: Basic Electronics
Previous Lesson: Electron Emission: Applications and Comparisons.
Topic: SEMI-CONDUCTORS Concept of semi-conductor, semi-conductor materials and doping
Subject Matter: concept of semiconductor, semiconductor materials such as silicon and germanium, doping of semiconductor materials, formation of intrinsic and extrinsic semiconductors

Specific Objectives

By the end of the lesson, pupils should be able to:

Cognitive Domain:

Define a semiconductor.
List common semiconductor materials.
Explain the process of doping in semiconductors.
Differentiate between intrinsic and extrinsic semiconductors.

Affective Domain:

Appreciate the importance of semiconductors in modern electronic devices.
Show interest in the study of electronic components.

Psychomotor Domain:

Identify pictures of semiconductor materials like silicon and germanium.
Draw simple diagrams illustrating doped semiconductors.

Participate actively in class discussions on semiconductors.
Share ideas on the applications of semiconductors.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum for Basic Technology.
State Unified Scheme of Work for Basic Electronics (SSS 1).
Basic Electronics for Senior Secondary Schools by A. O. Alabi.

Instructional Materials

The teacher will teach this lesson with the aid of:

Pictures of semiconductor materials (e.g., silicon wafers).
Software simulations showing semiconductor behaviour (if available).
Whiteboard and markers.

Rationale for the Lesson

This lesson helps pupils understand the fundamental building blocks of modern electronic devices. Understanding semiconductors explains how many everyday gadgets, from phones to computers, function, which is important for future studies in science and technology.

Prerequisite/Previous Knowledge

Pupils are expected to have a basic understanding of electricity, conductors, and insulators from previous lessons.

Lesson Content/Board Summary

SEMI-CONDUCTORS

1. Concept of Semiconductor

A semiconductor is a material that has electrical conductivity intermediate between that of a conductor (like copper) and an insulator (like glass). Its conductivity can be controlled by adding impurities or by changing temperature.

2. Semiconductor Materials

The following are common semiconductor materials:

Silicon (Si): Widely used in electronic devices due to its abundance and stable properties.
Germanium (Ge): An older semiconductor material, less common than silicon but still used in some applications.

3. Doping of Semiconductor Materials

Doping is the process of intentionally introducing impurities into an intrinsic (pure) semiconductor to modify its electrical properties. This process increases the number of charge carriers (electrons or holes) in the semiconductor.

4. Intrinsic Semiconductors

An intrinsic semiconductor is a pure semiconductor material without any added impurities. Its conductivity is very low at room temperature because it has a limited number of free electrons and holes generated by thermal energy.

5. Extrinsic Semiconductors

An extrinsic semiconductor is a semiconductor whose electrical conductivity has been enhanced by doping with impurities. There are two main types of extrinsic semiconductors:

N-type Semiconductor: Formed by doping an intrinsic semiconductor with pentavalent impurities (e.g., Phosphorus, Arsenic). These impurities have 5 valence electrons, providing an excess free electron, making electrons the majority charge carriers.
P-type Semiconductor: Formed by doping an intrinsic semiconductor with trivalent impurities (e.g., Boron, Gallium). These impurities have 3 valence electrons, creating a “hole” (absence of an electron) in the crystal lattice, making holes the majority charge carriers.

Teaching Methods/Instructional Techniques

Discussion, Lecture, Demonstration, Question and Answer, Visual Aids

Instructional Procedures

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: The teacher greets the pupils and asks them to recall what they know about conductors and insulators. The teacher then introduces the topic of semiconductors as materials that fall between these two categories.
Pupils’ Activity: Pupils respond to the teacher’s questions and listen attentively to the introduction.
Learning Point: Pupils recall previous knowledge and are prepared for the new topic.

Step 2: Explanation of Concept of Semiconductor

Time: 10 minutes
Teaching Skill: Explanation/Lecture
Teacher’s Activity: The teacher defines a semiconductor and explains its unique electrical properties, highlighting how it differs from conductors and insulators. The teacher writes key points on the board.
Pupils’ Activity: Pupils listen, take notes, and ask questions for clarification.
Learning Point: Pupils understand the basic concept and definition of a semiconductor.

Step 3: Identification of Semiconductor Materials

Time: 5 minutes
Teaching Skill: Demonstration/Listing
Teacher’s Activity: The teacher displays pictures of silicon and germanium and lists them as common semiconductor materials, briefly mentioning their uses.
Pupils’ Activity: Pupils observe the pictures and note down the names of the materials.
Learning Point: Pupils can identify and list common semiconductor materials.

Step 4: Explanation of Doping

Time: 5 minutes
Teaching Skill: Explanation/Illustrative
Teacher’s Activity: The teacher explains the process of doping, emphasizing that it is the intentional addition of impurities to change conductivity. The teacher uses simple analogies to illustrate the concept.
Pupils’ Activity: Pupils listen and try to grasp the concept of doping.
Learning Point: Pupils understand what doping is and its purpose.

Step 5: Discussion on Intrinsic Semiconductors

Time: 5 minutes
Teaching Skill: Discussion/Clarification
Teacher’s Activity: The teacher explains what an intrinsic semiconductor is, focusing on its pure state and low conductivity. The teacher engages pupils in a short discussion to ensure understanding.
Pupils’ Activity: Pupils contribute to the discussion and ask questions related to intrinsic semiconductors.
Learning Point: Pupils understand the characteristics of intrinsic semiconductors.

Step 6: Discussion on Extrinsic Semiconductors (N-type and P-type)

Time: 5 minutes
Teaching Skill: Explanation/Differentiation
Teacher’s Activity: The teacher explains the two types of extrinsic semiconductors: N-type and P-type. The teacher describes the type of impurities used for each and how they affect the charge carriers.
Pupils’ Activity: Pupils listen, take notes, and differentiate between N-type and P-type semiconductors.
Learning Point: Pupils can distinguish between N-type and P-type extrinsic semiconductors.

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

Define a semiconductor.
Mention two common semiconductor materials.
What is doping in the context of semiconductors?
State the difference between an intrinsic and an extrinsic semiconductor.
List the two types of extrinsic semiconductors.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 5 minutes
Teaching Skill: Summarization
Teacher’s Activity: The teacher summarizes the key points of the lesson, reiterating the definition of semiconductors, the materials, and the doping process. The teacher then gives pupils an assignment to research practical applications of semiconductors.
Pupils’ Activity: Pupils listen to the summary and note down the assignment.
Learning Point: Pupils reinforce their understanding and are given a task for further learning.

Lesson Keywords

Semiconductor – A material with electrical conductivity between that of a conductor and an insulator.
Doping – The process of adding impurities to a semiconductor to change its electrical properties.
Silicon (Si) – A common semiconductor material.
Germanium (Ge) – Another common semiconductor material.
Intrinsic Semiconductor – A pure semiconductor material.
Extrinsic Semiconductor – A doped semiconductor material.
N-type Semiconductor – Extrinsic semiconductor with excess electrons as majority carriers.
P-type Semiconductor – Extrinsic semiconductor with holes as majority carriers.

Differentiation

For pupils who grasp concepts quickly, the teacher can provide additional challenges such as asking about the valency of dopant atoms or real-world examples of N-type and P-type materials. For pupils who need more support, the teacher will use more visual aids and repeat explanations, providing simplified examples and one-on-one guidance.

Note for teachers using this lesson plan

Teachers should ensure they have clear visual aids for semiconductor materials and simple diagrams illustrating doping. Encourage pupils to ask questions and relate the concepts to everyday electronic devices to make the lesson more engaging and relevant.