Charge spectroscopy of Si nanocrystals in a SiO2 matrix

For the first time, the recharging of semiconductor nanocrystals (NCs) embedded in a dielectric matrix was studied by means of charge deep-level transient spectroscopy (Q-DLTS). Our measured Q-DLTS spectra were found to arise from two or three transient processes with different activation energies observed in different temperature ranges. We suggest that these are associated with quantum-confined electronic states in Si NCs. The data obtained were used to extract the energy position of NC levels, the size of NCs, and the typical recharging times of weakly coupled NCs. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)