Advanced research into the growth mechanism and optical properties of wurtzite ZnSe quantum dots

Zinc selenide (ZnSe) quantum dots (QDs) with the hexagonal wurtzite structure were successfully prepared using a safe, controllable ethylenediamine-mediated solvothermal method in the absence of surfactants. This new synthesis process of the wurtzite ZnSe QDs was described and the growth mechanism of QDs was proposed. The room-temperature photoluminescence (PL) spectrum of the wurtzite ZnSe QDs (about 4 nm) showed a strong near-band-edge emission peak at 422 nm. The near-band-edge emission peak was blue-shifted compared to that of the bulk ZnSe due to the quantum confinement effects; the peak also displayed a progressive red-shift with increasing the excitation power and an associated reduction in peak energy of up to 300 meV. Band gap renormalization in the electron-hole plasma regime might be used to explain this phenomenon. No previous published research regarding the observed excitation-power-dependent PL properties of the wurtzite ZnSe QDs had been found. Our experimental results contributed valuable insights into the optical properties of the wurtzite ZnSe QDs; with potential applications in optoelectronics and other areas where advanced uniformly-structured nanocrystalline semiconductor materials were finding increased use.