Auger recombination as a probe of the Mott transition in semiconductor nanocrystals

We report on picosecond dynamics of photoexcited carriers in CsPbCl3 nanocrystals in a CsCl host. For low carrier densities, photoexcited carriers form excitons, which decay with a characteristic time constant of 170 ps at 300 K. Under strong photoexcitation, we have observed the Auger recombination with the Auger coefficient C approximate to 10(-29) cm(6) s(-1). We have identified the onset of the Auger recombination at the carrier densities of approximate to 10(20) cm(-3) as the Mott-like transition from excitons to electron-hole plasma in nanocrystals. (C) 2000 American Institute of Physics. [S0003-6951(00)02520-1].