Changes

A quantum well works in a very similar way.  Electrical forces keep charged particles (such as [[electron]]s) inside the well, just like [[gravity]] keeps a ball inside the Grand Canyon.

A quantum well works in a very similar way.  Electrical forces keep charged particles (such as [[electron]]s) inside the well, just like [[gravity]] keeps a ball inside the Grand Canyon.

A second important difference is that quantum wells are very small (about 1000th of the width of a human hair).  At these scales, [[quantum mechanics|quantum effects]] come into play.  This means that the electron may only have certain, fixed energy levels.  Think of this as being like standing on a ladder - you can only stand on the rungs, not the gaps in-between.

A second important difference is that quantum wells are very small (about 1000th of the width of a human hair).  At these scales, [[quantum mechanics|quantum effects]] come into play.  This means that the electron may only have certain, fixed [[energy level]]s.  Think of this as being like standing on a ladder - you can only stand on the rungs, not the gaps in-between.

== Why this is useful ==

== Why this is useful ==