Nanometer-sized semiconductor particles are currently being intensivel
y investigated in many fields of physics and chemistry-especially sinc
e the discovery of visible luminescence in porous silicon. This is one
of the first papers to concentrate on the synthesis of IV-IV nanopart
icles. A purely wet-chemical room-temperature synthesis is described t
hat leads to stable nanometer colloidal germanium particles after lase
r illumination. The size of the crystallites can be controlled by adju
sting the illumination conditions. The preparation technique detailed
here is not restricted to germanium but can also be applied to other I
V-IV semiconductor particles.