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2020/21 Undergraduate Module Catalogue

ELEC2240 Transistors and Optoelectronic Devices

20 creditsClass Size: 100

Module manager: Professor Giles Davies

Taught: Semesters 1 & 2 (Sep to Jun) View Timetable

Year running 2020/21

This module is not approved as a discovery module

Module summary

The teaching and assessment methods shown below will be kept under review during 2020-21. In particular, if conditions allow for alternative formats of delivery, we may amend the timetable and schedule appropriate classes in addition to (or in place of) the Online Learning Workshops. For Semester 2 (from January 2021), we anticipate that this will be most likely, in which case online teaching will be substituted for traditional face-to-face teaching methods, including lectures and practical classes. ‘Independent online learning’ will involve watching pre-recorded lecture material or screen-casts, engaging in learning activities such as online worked examples or remote/virtual laboratory work, etc. Students will be expected to fully engage with all of these activities. The time commitment for independent online learning, and also the frequency and duration of Online Learning Workshops, are approximate and intended as a guide only. Further details will be confirmed when the module commences.


The aim of this module is to give students specialist knowledge and understanding of the properties of the semiconductor materials and devices used for transistors and optoelectronic devices. Students will gain an understanding of the principles of semiconductor physics, including an introduction to quantum mechanics and the design and analysis of important representative devices.

Learning outcomes
On completion of this module students should be able to:

1. Explain the operation of the p-n junction diode, and be able to analyse its properties using its bandstructure.
2. Explain the operation of light emitting diode, and how they are fabricated.
3. Understand the basic operation of a laser, the concept of population inversion, and how a laser fundamentally operates differently from a LED.
4. Understand the importance of bandstructure in the design and operation of a range of electronic and optoelectronic devices, and appreciate the role of quantum mechanics in underpinning a material's bandstructure.
5. Explain how a two-dimensional electron system can be formed in silicon MOSFETs and in GaAs-AlGaAs heterojunctions, the concept of field effect, and how these devices can show transistor action.
6. Understand the basic operation principles of photodiodes as photodetectors and the factors influencing their efficiency and responsivity.
7. Understand the use of p-n junctions in different configurations as photovoltaic devices, and the characteristics of solar cells made of different materials.
8. Understand the operation of the bipolar junction transistor, and be able to utilize its properties in different applications.


Topics may include, but are not limited to:

Revision of bandstructures for metals and semiconductors, doping, n- and p-type semiconductors, Fermi energy, law of mass action
Revision of p-n junction diodes. Depletion region, built-in potential. Behaviour of diode as a function of forward and reverse bias in terms of bandstructure. Derive Shockley diode equation
The light emitting diode (LED). Homojunction and double-heterojunction LEDs. Overview of molecular beam epitaxy as a method to fabricate layered semiconductor devices
Elementary quantum mechanics. Light as a wave, the electron as a wave. The infinite potential well (particle-in-the-box), subbands, quantized energies, the electron wave function
Energy levels in atoms, molecules, and crystalline materials. Origin of energy bands. Dispersion curves. Effective mass. Bloch electron waves
Return to LEDs. Comparison of direct/indirect bandgap semiconductors. Emission spectrum and characteristics of red LED
Spontaneous vs stimulated emission. Population inversion. The LASER. Comparison of the ruby laser, the erbium-doped fibre laser, the He-Ne gas laser. Gain curve, laser cavity, Fabry-Pérot modes
The pn-junction diode laser, homojunction and heterojunction devices. Quantum-confined semiconductor lasers. The quantum cascade laser
The bipolar transistor in common base and common emitter configurations and their application as amplifiers
The junction field effect transistor (JFET) and the MOSFET and their use as amplifiers
The principle of the p-n junction photodiode, Ramo’s theorem and external photocurrent. Absorption coefficient and photodiode materials (indirect vs indirect band gap). Quantum efficiency and responsivity. The pin photodiode and the avalanche photodiode
The solar energy spectrum. Photovoltaic device principles. p-n junction photovoltaic I-V characteristics. Solar cells materials, devices and efficiencies

Teaching methods

Due to COVID-19, teaching and assessment activities are being kept under review - see module enrolment pages for information

Delivery typeNumberLength hoursStudent hours
Example Class81.008.00
Independent online learning hours64.00
Private study hours126.00
Total Contact hours10.00
Total hours (100hr per 10 credits)200.00

Private study

Students are expected to use private study time to consolidate the material covered in lectures, to undertake preparatory work for examples classes and to prepare for summative assessments.

Opportunities for Formative Feedback

Feedback will be mainly provided through the examples classes.

Methods of assessment

Due to COVID-19, teaching and assessment activities are being kept under review - see module enrolment pages for information

Assessment typeNotes% of formal assessment
Online AssessmentOnline Assignment/Test 325.00
Online AssessmentOnline Assignment/Test 435.00
Online AssessmentOnline Assignment/Test 115.00
Online AssessmentOnline Assignment/Test 225.00
Total percentage (Assessment Coursework)100.00

.Resits for ELEC and XJEL modules are subject to the School's Resit Policy and the Code of Practice on Assessment (CoPA), which are available on Minerva. Students should be aware that, for some modules, a resit may only be conducted on an internal basis (with tuition) in the next academic session.

Reading list

The reading list is available from the Library website

Last updated: 24/02/2021 16:36:22


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