Potential Role for Charged Dangling Bonds in Transient-Lesr of Light-Soaked a-Si:H

1992 ◽  
Vol 258 ◽  
Author(s):  
Z. M. Saleh ◽  
H. Tarui ◽  
S. Tsuda ◽  
S. Nakano ◽  
Y. Kuwano

ABSTRACTTransient light-induced electron spin resonance (LESR) at 120 K, has been used to investigate deep defects in a-Si:H through changes in the lineshape. When the lineshape is deconvoluted into narrow and broad components, the narrow component is found to decrease, relative to the broad component, with increasing light-soaking time. Similar changes are not observed, however, in as-deposited or annealed films regardless of deposition and annealing conditions. An important role for charged dangling bonds is proposed to explain these changes and we suggest that intrinsic (stable) and light-induced (metastable) defects play different roles in transient-LESR and may occupy different energy distributions in the gap.

1999 ◽  
Vol 59 (7) ◽  
pp. 4849-4857 ◽  
Author(s):  
T. Umeda ◽  
S. Yamasaki ◽  
J. Isoya ◽  
K. Tanaka

2000 ◽  
Vol 638 ◽  
Author(s):  
K. Toshikiyo ◽  
M. Tokunaga ◽  
S. Takeoka ◽  
M. Fujii ◽  
S. Hayashi

AbstractDangling bond defects in Si1−xGex alloy nanocrystals (nc-Si1−xGex) as small as 4 nm in diameter embedded in SiO2 thin films were studied by electron spin resonance (ESR), and the effects of the defects on photoluminescence (PL) properties were discussed. It was found that the ESR spectrum is a superposition of signals from Si and Ge dangling bonds at the interfaces between nc-Si1−xGex and SiO2 matrices (Si and Ge Pb centers). As Ge concentration increased, the intensity of the signal from the Ge Pb centers increased, while that from the Si Pb centers was almost independent of Ge concentration. The increase in the number of Ge Pb centers was accompanied by strong quenching of the PL. The observed correlation between the two measurements suggests that Ge Pb centers act as efficient non-radiative recombination centers for photogenerated carriers, resulting in the quenching of the PL.


1999 ◽  
Vol 593 ◽  
Author(s):  
A. Manivannan ◽  
A. Punnoose ◽  
M.S. Seehra

ABSTRACTInteraction of oxygen with three commercial activated carbons (GX203, P1400 and MEED50 supplied by PICA USA Inc., with BET surface areas of 1000, 1150 and 2000 m2/g respectively) is investigated using 9 GHz electron spin resonance (ESR) spectroscopy. All three carbons give a single ESR line with g = 2.0028(3), but the linewidth ΔH and the spin concentration Ns, are strongly affected by exposure to oxygen. The ESR parameters (g, ΔH, Ns) are measured for different partial pressures of oxygen. For the highly evacuated samples, δH ≃ 1.2 Oe and Ns ≃ 1019/gm and these results are interpreted in terms of uncompensated surface dangling bonds. Oxygen exposure broadens the line and reduces Ns, in direct relation to the surface areas of the carbons and the effect is reversible. Possible effects of the paramagnetic oxygen on dangling bonds are discussed.


1993 ◽  
Vol 74 (10) ◽  
pp. 6313-6316 ◽  
Author(s):  
Tao Wang ◽  
Lide Zhang ◽  
Xiaojun Fan ◽  
Jitong Hu ◽  
Jimei Mo

2003 ◽  
Vol 762 ◽  
Author(s):  
K. Brendel ◽  
N. H. Nickel ◽  
K. Lips ◽  
W. Fuhs

AbstractDoped and undoped laser crystallized polycrystalline silicon was investigated by electron-spin-resonance experiments. In P-doped samples two resonance are detected at g = 2.0053 and g = 1.998 which are due to silicon dangling bonds and conducting electrons, respectively. After crystallization a large amount of hydrogen remains in the samples. This residual hydrogen can be activated to reduce the spin density by passivating dangling-bonds. The temperature dependent investigation of the conducting electron resonance reveals that the susceptibility can be described by the sum of Pauli and Curie paramagnetism. The data are discussed in terms of models developed for single crystal and microcrystalline silicon.


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