Etched Quantum Dots Shape Up as Single Photon Emitters, NIST
Tests Show From NIST Tech Beat: February 22, 2011 Contact: Laura
Ost Like snowflakes or fingerprints, no two quantum dots are
identical. But a new etching method for shaping and positioning
these semiconductor nanocrystals might change that. What's more,
tests at the National Institute of Standards and Technology
(NIST) confirm that etched quantum dots emit single particles of
light (photons), boosting prospects for powering new types of
devices for quantum communications. The conventional way to
build quantum dots—at NIST and elsewhere—is to grow them like
crystals in a solution, but this somewhat haphazard process
results in irregular shapes. The new, more precise process was
developed by NIST postdoctoral researcher Varun Verma when he
was a student at the University of Illinois. Verma uses electron
beam lithography and etching to carve quantum dots inside a
semiconductor sandwich (called a quantum well) that confines
particles in two dimensions.