OT? Infrared control and such

[Ian Fritz]

Martin --

This isn't quite right. Si is an indirect bandgap semiconductor and cannot
be used as an LED (or laser). As a detector it operates throughout both the
visible and near IR, ca 350-1100 nm. For LED's, compound semiconductors are
used, both for visible and NIR.

  Ian

>
> :::There are (roughly speaking) infrared equivalents of LED/LDR's at work
here,
> :::yes?
>
> Yep, but in contrast to CdS LDRs infrared sending/detecting uses
monolithic
> silicon. It is the "natural mode" of Si to deal with infrared.
> Visible light will need compound semiconductors.
>