Page 247 - Photonics Essentials an introduction with experiments

Measurements in Photonics

Measurements in Photonics 241

Take some time to experiment with the curve tracer, using a resis-
tor instead of your device. When you turn on the tracer, note that the
current scale is 2 A and the voltage scale is 2 V per division. These
values are very large. You should adjust the curve tracer to the appro-
priate scales for both current and voltage before applying any voltage
to the device to be tested. Typical values of voltage are –5 V to +2 V.
Typical values of current are 10 A to 100 mA in forward bias, and
only 10 A in reverse bias. Be aware at all times which lead is the an-
ode and which lead is the cathode of your diodes. In forward bias, the
anode is biased positive with respect to the cathode.

10.11 Summary
Basic optoelectronic device characterization is easy to learn but it
takes skill and patience to make high-precision measurements. You
will be able to note your own progress in setting up experiments and
obtaining measurements as you use this book. Although experience is
a great teacher, you can often learn even more by reading the owner’s
manual of your instruments carefully. There you will often find en-
lightening details of the principles of operation and suggested experi-
mental set-up schematic diagrams.
A critical detail in most experiments is mounting the sample so that
it can be characterized. The most important concern is stabilizing the
device so that it does not move during the measurement. The time you
spend initially to mount a device socket so that it can be attached to a
x-y-z manipulator will pay back big dividends in the validity of your
measurements and also in reduced mechanical strain on the device
electrical leads.

Bibliography
R. F. Pierret, Semiconductor Device Fundamentals, Reading, Addison-Wes-
ley, 1996. This book is rich in techniques and set-ups for experimental
characterization of electronic devices.
J. Wilson and J. Hawkes, Optoelectronics, 3rd Edition, London, Prentice-Hall
Europe, 1998.
E. Hecht, Optics, 2nd edition, Reading, Addison-Wesley, 1987.
Also see the User’s Manual of each instrument.

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