I-V Curve Characteristics of Semiconductors on the cheap (Mostly…) *WIP*

The need for this testing setup arose while I was playing with making semiconductors from scratch. Specifically simple diodes from complete scratch. One being Cuprous Oxide, with interest in Aluminum Oxide as well.

While poking around with a graphite lead on the Copper Oxide layer, it quickly dawned on me that there was no really easy way to tell if I actually touched upon an active semiconducting layer. Probing a site with a multimeter and looking for some characteristics[what?] then swapping the leads to seeing if current is blocked in one direction, is one way, but slow and easier said than done. So I-V tracing got my attention.

What we need

  1. Material/Device under test
  2. Voltage and Current test rig
  3. Measuring device
  4. Function generator

What we have

Material/Device under test

Control Device: Silicon Diode

From the parts bin, tested with multimeter and/or LCR meter

Target Material: Copper Oxide

Home made semiconductor, see Cuprous Oxide – Copper(I) Oxide – Cu2O Diode

Voltage and Current Test Rig

Common configurations

Our choice setup

Measuring device

Two channels, both voltage in time domain

Oscilloscope

DSO vs CRT

Possibly Arduino

Function generator

Requirements:
* Sine wave
* Frequency: 20-100Hz1, let's say center frequency of 40Hz

555 Timer with square to sine wave circuitry

What I've tried:
* 555 with passive component low-pass filter
* Results in huge loss of voltage

Next steps:
* Still using the 555 as the oscillator, but using Op-Amps as an active filter.
* Specifically a cascade of integrator and low-pass filter

Links:
* Integrator/Low Pass Filter
* TI Bulletin
* Better "Explanation" of above three Op-Amp circuit
* Interesting Active band pass filter online calculator

Leave a Reply

Your email address will not be published. Required fields are marked *