Two-Dimensional Excitons in Siloxene

1993 ◽  
Vol 298 ◽  
Author(s):  
M. S. Brandt ◽  
M. Rosenbauer ◽  
M. Stutzmann
Keyword(s):  
Magnetic Resonance ◽  
Porous Silicon ◽  
Dipolar Coupling ◽  
Luminescence Properties ◽  
Two Dimensional ◽  
Photoluminescence Excitation ◽  
Luminescence Process ◽  
Optically Detected ◽  
Gaussian Line ◽  
Triplet Excitons

AbstractThe luminescence properties of two different modifications of siloxene are studied with photoluminescence excitation spectroscopy (PLE) und optically detected magnetic resonance (ODMR). The luminescence of as prepared siloxene, which consists of isolated silicon planes, is resonantly excited at the bandgap, indicating a direct bandstructure. The observation of Δm = ±2 transitions in ODMR shows that triplet excitons contribute to the luminescence process. In contrast, annealed siloxene consisting primarily of six-membered silicon rings shows a PLE typical of a material with an indirect bandgap. The ODMR signal of annealed siloxene and of porous silicon show the same Gaussian line with a typical width of 400 G, which can arise from strong dipolar coupling of an electron and a hole ≈ 5Å apart.

Visible Luminescence from Porous Silicon and Siloxene: Recent Results

1992 ◽  
Vol 283 ◽  
Author(s):  
H. D. Fuchs ◽  
M. Rosenbauer ◽  
M. S. Brandt ◽  
S. Ernst ◽  
S. Finkbeiner ◽  
...  
Keyword(s):  
Optical Properties ◽  
Magnetic Resonance ◽  
Porous Silicon ◽  
Time Dependent ◽  
Photoluminescence Excitation ◽  
Porous Si ◽  
Green Luminescence ◽  
Visible Luminescence ◽  
Optically Detected ◽  
Insight Into

ABSTRACTThe optical properties of porous Si (p-Si) are compared to those of siloxene and its derivatives in order to gain more insight into the mechanism of the luminescence observed in p-Si. We report new results of photoluminescence (PL), photoluminescence excitation (PLE), time-dependent and pressure-dependent photoluminescence, and optically detected magnetic resonance (ODMR). Important information about the structural, electronic, and microscopic nature of the two classes of materials are deduced from these experiments. Annealed siloxene and p-Si show very similar properties, suggesting that siloxene-related structures, e.g. electrically isolated Si6-rings, might be responsible for the luminescence in p-Si. The Si-planes in as-prepared siloxene, with their green luminescence, are metastable and are readily oxidized into red-luminescent siloxene configurations.

Polarons and Triplet Excitons in C60: An Optically Detected Magnetic Resonance (Odmr) and Light-Induced Esr (Lesr) Study

1992 ◽  
Vol 270 ◽  
Author(s):  
P. A. Lane ◽  
L. S. Swanson ◽  
Q.-X. Ni ◽  
J. Shinar ◽  
J Engel ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Conjugated Polymers ◽  
Glass Matrix ◽  
Membered Ring ◽  
X Band ◽  
Optically Detected Magnetic Resonance ◽  
Optically Detected ◽  
Triplet Excitons

ABSTRACTThe photoluminescence (PL), X-band ODMR. and LESR of C60 films and C60 isolated in a toluene/polystyrene glass matrix (C60:T/PS) is described. The delocalized triplet LESR and ODMR of C60:T/PS are similar to previously reported LESR. In films, however, the ODMR indicates that the delocalized triplet is larger and distorted by neighboring molecules. In addition, another, localized triplet, and a narrow PL-enhancing line at g = 2.0017 ± 0.0005 are observed. These features are similar to those observed in several π-conjugated polymers. The former is attributed to a localized triplet of size similar to a 5- or 6-membered ring, tentatively on a face adjacent to another C60 molecule; the latter is believed to result from intermolecular polaron recombination.

Polarons and triplet excitons in C60 glasses and films: An optically detected magnetic resonance (ODMR) study

1993 ◽  
Vol 56 (2-3) ◽  
pp. 3086-3091 ◽  
Author(s):  
P.A. Lane ◽  
L.S. Swanson ◽  
J. Shinar ◽  
J. Engel ◽  
T.J. Barton ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Optically Detected Magnetic Resonance ◽  
Optically Detected ◽  
Triplet Excitons

Optically Detected Magnetic Resonance Investigations on Rapidly Thermally Oxidized Porous Silicon

1993 ◽  
Vol 143-147 ◽  
pp. 1459-1462
Author(s):  
D.M. Hofmann ◽  
B.K. Meyer ◽  
W. Stadler ◽  
A. Kux ◽  
V. Petrova-Koch ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Porous Silicon ◽  
Optically Detected Magnetic Resonance ◽  
Oxidized Porous Silicon ◽  
Optically Detected
Sign in / Sign up

Export Citation Format

Share Document