Optical absorption properties of Ge2–44 and P-doped Ge nanoparticles

Abstract

The optical absorption properties of non-crystalline and crystalline Ge nanoparticles with the sizes from ∼2.5 to 15 Å have been studied at the B3LYP/6-31G level using time-dependent density functional theory. Hydrogen passivation and phosphorus doping on some selected Ge nanoparticles were also calculated. With the increase of cluster size, the optical absorption spectra of the non-crystalline Ge nanoparticles change from many peaks to a continuous broad band and at the same time exhibit a systematic red-shift. Doping phosphorus also causes the absorption spectra to shift toward the lower energy region for both non-crystalline and crystalline Ge nanoparticles. The non-crystalline Ge nanoparticles are found to have stronger absorption in the visible region in comparison with the crystalline ones, regardless phosphorus doping.

Bacterial Toxicity of Germanium Nanocrystals Induced by Doping with Boron and Phosphorus

“…Typically, p-type semiconductor nanocrystals are synthesized by doping intrinsic materials with trivalent impurities (such as boron, aluminum, or gallium) during fabrication while n-type semiconductor nanocrystals are created via the incorporation of pentavalent dopants (such as phosphorus, arsenic, or antimony). For semiconductor nanocrystals, the intentional doping plays a critical role in enhancing the materials’ original electrical, optical, , and magnetic properties, leading to a wide range of applications for transistors, , photovoltaics, thermoelectric devices, and light-emitting devices …”

“…Typically, p-type semiconductor nanocrystals are synthesized by doping intrinsic materials with trivalent impurities (such as boron, aluminum, or gallium) during fabrication while n-type semiconductor nanocrystals are created via the incorporation of pentavalent dopants (such as phosphorus, arsenic, or antimony). For semiconductor nanocrystals, the intentional doping plays a critical role in enhancing the materials' original electrical, 33 optical, 34,35 and magnetic 36 properties, leading to a wide range of applications for transistors, 23,37 photovoltaics, 38 thermoelectric devices, 39 and light-emitting devices. 40 However, alongside the incorporation of p-/n-type dopants, redundant holes (h + ) or electrons (e − ) are introduced into the nanoscale network as well, 41 making it possible to generate reactive oxygen species (ROS) via two potential pathways: oxidation of water at the surface of nanocrystals (OH − + h + → • OH) 42 or reduction of molecular oxygen (O 2 + e − → O 2…”