Quantum size effects in nanocrystalline semiconducting titania layers prepared by anodic oxidative hydrolysis of titanium trichloride

TLDR: In this article, the size effects in thin semiconducting layers were first treated theoretically by Shinada and Sugano? using a model of a two-dimensional hydrogen atom, and the calculated optical interband transition energies are related to the UV-vis absorption spectra of layered semiconductors, such as gallium chalcogenides? Bi13? Pb12,394 and CdS.S.

Abstract: nm). Theseeffects have been extensively studied for small particles in colloidal solution (Q-particles) and thin solid films (Q-layers or Q-wells). For the latter, various applications in optoelectronics are foreseen.' The size effects in thin semiconducting layers were first treated theoretically by Shinada and Sugano? using a model of a two- dimensional hydrogen atom. The calculated optical interband transition energies are related to the UV-vis absorption spectra of layered semiconductors, such as gallium chalcogenides? Bi13? Pb12,394 and CdS.S.6 The most pronounced effect is an increase in the band gap energy compared to that of the bulk semicon- ductors and sometimes also Occurrence of exciton absorptions in the region of onset of the continuous absorption.2" For an anisotropic layered crystallite, the band gap shift, AE,, is described by the equation's where