More advanced texts discuss these devices quantitatively, and use relatively few visualization tools. Most standard introductory texts do not mention the quantum properties of LEDs or any similar devices. To understand this relationship the students must learn how the energy bands respond to changes in applied voltage or incident light. Since the primary goal of the activities is to enable students to understand the quantum effects in an LED, the students must be able to understand the relationship between the energy bands of the material of an LED and its electrical and spectral characteristics.
To capitalize on this recognition, we are have designed and tested a series of activities that will enable the students to qualitatively explain how an LED is able to emit light. The ubiquitous light emitting diode (LED) is recognized by almost every student as a small red or green light that indicates that some electronic gadget such as a CD player or computer disk drive is operating. To reach these students we are concentrating on the development of activities which integrate hands-on experiments, computer visualizations, and multimedia materials in addition to the more traditional written materials.ĭuring the first eight months of this project we have concentrated on developing activities with a device that requires knowledge of quantum physics to understand how it works. The primary audience for these materials is high school or introductory undergraduate students who do not have a background in higher level mathematics or quantum physics. INTRODUCTION The Visual Quantum Mechanics 1,2 project is developing materials to help students learn quantum physics. The current version of the program contains modifications based on these field tests. We have field tested the program along with associated materials in both high school and university environments. The flexibility of the program allows it to be used by students over a range of academic levels.
The program is available for Windows Ô and Macintosh Ô platforms. No prior knowledge of higher level mathematics is required to use the program. The device once created, can then be incorporated into a circuit where the students can observe the energy bands, the I-V graph, as well as the intensity spectrum of the device in response to the changes in applied voltage and/or incident light.
While creating the device, students can observe the changes in the energy bands and Fermi level as a response to doping. This program enables students to create the device starting with two pieces of intrinsic semiconductor material, and doping them appropriately to create a p-n junction device of their choice.
We present here a computer program – the Semiconductor Device Simulator which simulates the working of three p-n junction devices - the LED, the solar cell, and the tunnel diode.
Kansas State University, Physics Department, 116 Cardwell Hall, Manhattan, KS 66506-2601 COMPUTER SIMULATION OF P-N JUNCTION DEVICESĬOMPUTER SIMULATION OF P-N JUNCTION DEVICES N.Sanjay Rebello, Chandramouli Ravipati, Dean A.