Effect of quantum confinement on higher transitions in HgTe nanocrystals

Spectroscopic ellipsometry measurements on 1–10 bilayers of HgTe nanocrystals and polymer were performed in the spectral range from 0.5 to 5 eV. The experiments show that the band model, respectively, band energy shifts due to quantization, can be applied onto nanocrystals with as few as five unit cells in diameter. These nanocrystals exhibit strong transitions at higher critical points. The critical point energies shift up to 0.4 eV. It turns out that transitions between bands which are closer to the Fermi energy and have a smaller carrier mass are more strongly affected by quantum confinement.