Doping effects in amorphous oxides

Abstract

Impurity doping of crystalline Si is one of the most striking techniques in semiconductor technology. A rigid and perfect crystalline lattice is prerequisite for effective doping. However, it has been reported to date that introducing a small amount of impurities drastically improves also the properties of amorphous materials. This paper reviews three pronounced doping effects on optical and electrical properties of amorphous oxides; i.e., (i) F-doping of silica glass to improve the vacuum-ultraviolet optical transmission and radiation toughness, (ii) codoping effects on solubility enhancement of rare earth ions in silica glass melt, and (iii) electron-carrier generation in transparent amorphous oxide semiconductors. It is emphasized that effectiveness of electron doping is determined by the magnitude of electron affinity and stabilization energy of a dopant. Importance of the local structure formed around a dopant ion and the location of conduction band minimum measured from the vacuum level is addressed to understand the doping effects in amorphous oxides.

Significance of host׳s intrinsic absorption band tailing on Ce3+ luminescence quantum yield in borate glass

“…Moreover, the weak absorption due to defect centers shows a hump at about 4-5 eV and spans over a wide spectral region. The defect absorption arises due to the presence of various kinds of point defects in glass such as the wrong bonds, dangling bonds, non-bridging oxygen ions, vacancies, impurities, etc, forming localized states in the band-gap region [12][13][14][15][16]. These Gaussian-like localized distribution exhibit weak absorption bands below the Urbach tail, which together gives rise to an extended band tailing to the fundamental absorption of host glass.…”

Optimization of a gadolinium‐rich oxyhalide glass scintillator for gamma ray spectroscopy

“…Intense emission is typically observed when the conduction band of the host material is at a high energy level relative to the excited 5D states of Ce 3+ , as in the case of Y 3 Al 5 O 12 :Ce. 17 Fluoride glasses also benefit from lower phonon energies than oxide glasses leading to increased quantum efficiency for luminescence. 15 To reduce the adverse effect of high Gd content which lowers the band gap of the host glass, a high F content was incorporated into the oxide glass matrix through addition of LiF (33.3 mol%).…”

Impact of an Interfacial Layer on the Electrical Performance of p‐Channel Tin Monoxide Field‐Effect Transistors

“…Therefore, we believe that the higher V TH and SS values in the p‐channel SnO FETs with SiO 2 dielectric compared with that of the SiOF/SiO 2 dielectric come from the larger D it,max values near the VBM of SnO . Conversely, in the case of the SiOF interface layer, fluorine atoms incorporated into the SiO 2 are likely to reduce the interfacial traps states, which means that the Fermi level become less pinned near a VBM of the p‐type SnO. Indeed, a reduction in the D it,max value for the SnO FETs with SiOF/SiO 2 dielectric was calculated to be 4.0 × 10 12 eV −1 cm −2 , compared to that of the SiO 2 dielectric.…”