Time-resolved photoluminescence in Mobil Composition of Matter-48

Abstract

Time-resolved photoluminescence and capacitance-voltage analysis of the neutral vacancy defect in silicon implanted Si O 2 on silicon substrate J. Appl. Phys. 96, 3025 (2004); 10.1063/1.1775041The elementary steps of the photodissociation and recombination reactions of iodine molecules enclosed in cages and channels of zeolite crystals: A femtosecond time-resolved study of the geometry effect

Enhanced photoresponse of a metal-oxide-semiconductor photodetector with silicon nanocrystals embedded in the oxide layer

“…17 The measured response time of the detector was around 10 ns presumably constrained by nonradiative lifetime ͑2.5 ns͒ as previously reported in mesoporous siliceous materials. 18 This value is much faster than those demonstrated by photoconductive detectors. 5,8 Hence, photoconductive gain was ruled out as a major mechanism in the enhancement of reverse photocurrents of our ITO/nc-Siembedded MS/ p-Si detectors.…”

Visible Photoluminescence from Photoinduced Molecular Species in Nanometer-Sized Oxides: Crystalline Al2O3 and Amorphous SiO2 Nanoparticles

“…Luminescent nanoparticles have attracted a great deal of attention because of their potential application as indicators and photon sources for a variety of biotechnology and information technology. , In particular, amorphous silica-based luminescent nanoparticles have been extensively studied and explored since an elaborate synthesis of size-controlled, monodisperse nano- to micrometer-sized silica particles is possible . To obtain luminescent silica particles, inorganic and/or organic emission centers are often incorporated into the particles, yielding stable light-emissive silica-based nanoparticles. − It should further be noted that nondoped amorphous silica-based materials also exhibit a broad photoluminescence (PL) band in the blue region of the visible spectrum (∼400 to ∼450 nm), − which is usually characterized by a PL decay on the time scale of nanoseconds. − The resulting emission quantum yield can exceed ∼20–30% at room temperature by carefully control of the preparation condition. ,− Thus, it has been recognized that silica itself is also promising for an efficient light-emitting material, providing environmentally friendly light emitters …”

“…Although the blue emission characteristics of amorphous silica and its related silica-based nanostructured materials are well recognized, the origin of the emission is still a matter of discussion. − It is also interesting to note that a number of nanostructured crystalline oxides, e.g., Al 2 O 3 , ,− MgO, − and ZnO, , exhibit a blue PL band as well on the time scale of nanoseconds. , Observation of the common blue PL features in these nanostructured amorphous and crystalline oxides allows one to assume that structurally similar emission centers will exist at the surface of respective oxides. It has often been believed that surface OH groups are responsible for the blue PL emission observed in many different types of oxides. ,,,,,,, However, the simple OH-based model cannot be accepted without reservations because of the following reasons.…”

“…It has often been believed that surface OH groups are responsible for the blue PL emission observed in many different types of oxides. ,,,,,,, However, the simple OH-based model cannot be accepted without reservations because of the following reasons. First, the OH groups both in free and hydrogen-bonded states do not practically absorb light in the wavelength region longer than ∼300 nm, − whereas the blue PL emission occurs most effectively by using ∼330 to ∼360 nm light for excitation. − ,− Second, the blue PL output is normally enhanced after appropriate thermal annealing at ∼300 to ∼600 °C, and annealing at higher temperatures ( T ≳ 600 °C) almost eliminates the blue PL emission. ,− However, free and/or H-bonded OH groups at the surface of oxides do not exhibit the corresponding annealing temperature dependence; − rather, a large number of residual OH groups are still present up to ∼800 °C at the surface of alumina, silica, − and magnesia . It is hence probable that the blue PL emission does not result simply from the surface OH groups as they are but from certain relevant emissive defects, although the true structural origin of the emission center is not unambiguously identified at present. ,, …”

Fabrication and Characterization of Photodetector Based on Porous Silicon

“…Chemical texturization of single crystal silicon is ineffective due to random distribution of the grain orientations [3] but this problem was overcome by pSi formation. Up to date, few papers were published on optoelectronic properties of Al/pSi/Si/Al photodetectors made by electrochemical anodization on high resistivity Si substrate (10-190 Ωcm) [4][5][6][7][8]. The published results showed higher responsivity and quantum efficiency for these structures than that for p-n Si photodiodes.…”