General and fast patterning of semiconductor nanocrystals by femtosecond laser direct writing

Semiconductor nanocrystals have shown remarkable performance in the field of displays, solar cells, and photodetectors. But, a rapid method to produce localized stable nanocrystals remains a challenge, impeding the step toward device miniaturization. Here, we present a general and fast approach, femtosecond laser direct writing, for manufacturing these nanocrystals as well as integrating them into substrates in one step. The high peak power of the femtosecond laser induces a nonlinear absorption of the CatX (Cat  =  Cd or Pb, X  =  S, Se or Te) precursor at the focal spot. Once the temperature reaches the nucleation temperature, the CatX nanocrystals form immediately. By moving the displacement platform, arbitrary microscale patterns made of nanoscale crystals are obtained, which shows great potential in high-resolution displays and on-chip light sources.