Temperature dependence of photoluminescence from CdS nanoclusters formed in the matrix of Langmuir‐Blodgett film

Abstract

In this paper photoluminescence from CdS nanoclusters formed in the matrix of Langmuir-Blodgett film has been investigated in the temperature range 5-300 K. The photoluminescence spectrum of the nanoclusters at 300 K consists of two bands at 2.9 and 2.1 eV. Temperature dependence of the high-energy band maximum deviates from the dependence of the energy bandgap of bulk CdS. The integrated PL intensity of this band decreases with increasing temperature up to 75 K, grows in a temperature range 150-230 K, and rapidly falls at temperatures higher 230 K. The experimental data have been explained within the framework of a model of recombination of carriers considering carrier transport between CdS nanoclusters. An energy of electron traps and activation energies of nonradiative recombination have been estimated to be about 120, 4 and 100 meV, respectively.