Made from aluminium gallium arsenide, the nanocrystals are 500 times narrower than a human hair and can be applied to ordinary glass as ultra-thin, lightweight films.
The «teats» are actually receptacles containing aluminium, gallium and arsenic; the «udders» are high - vacuum reaction chambers in which ultrathin layers of crystal are grown on circular wafers of gallium arsenide, 75 or 100 millimetres across.