Pulsed Esr Studies on Microcrystalline Silicon

1998 ◽  
Vol 507 ◽  
Author(s):  
C. Malten ◽  
F. Finger ◽  
J. Müller ◽  
S. Yamasaki
Keyword(s):  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Microcrystalline Silicon ◽  
Field Sweep ◽  
Conduction Electrons ◽  
Spin Lattice ◽  
Boron Doped ◽  
Pulse Echo ◽  
Broad Feature

ABSTRACTTwo-pulse-echo field-sweep spectra of boron-doped samples show in addition to dangling bonds (DB) a very broad feature of approximately 500 G width. This feature is the sum of several lines whose relative intensities change with doping and temperature. The total intensity increases with doping. The spin-lattice relaxation time TI of the resonance at g=1.998 referred to as conduction electrons (CE) has been studied for undoped and P-doped microcrystalline silicon. The discrepancy between T1 values previously reported has been resolved and the values for CE are at least two orders of magnitude smaller than those of the DB. In undoped samples cross-relaxation between the CE and DB spin systems might explain the similar T1 values obtained for CE and DB in inversion recovery measurements.

scholarly journals Spin-lattice relaxation time of conduction electrons inMgB2

2007 ◽  
Vol 76 (2) ◽  
Author(s):  
F. Simon ◽  
F. Murányi ◽  
T. Fehér ◽  
A. Jánossy ◽  
L. Forró ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Conduction Electrons ◽  
Spin Lattice Relaxation Time ◽  
Spin Lattice

Dipolar Measurements of Hydrogen in Amorphous Silicon

1992 ◽  
Vol 258 ◽  
Author(s):  
P. Hari ◽  
P.C. Taylor ◽  
R.A. Street
Keyword(s):  
Amorphous Silicon ◽  
Pulse Sequence ◽  
Lattice Relaxation ◽  
Dipolar Interaction ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Discharge System ◽  
Spin Lattice ◽  
Boron Doped ◽  
Foil Substrate

ABSTRACTThe dipolar interaction of hydrogen (∼ 10 at. %) in boron-doped amorphous silicon has been studied using the Jeener-Broekaert pulse sequence. The sample was prepared on an Al foil substrate at a temperature of 230°C using a standard glow discharge system (operating at 1 W rf power). The diborane/silane ration was 10-4. The same sample was removed from the Al substrate using dilute hydrochloric acid. The Jeener-Broekaert pulse sequence consists of three pulses: π/2|x′ – τ1 – π/4|y′ – τ2 – π/4|y′ – echo. We measured T1D, the dipolar spin lattice relaxation time, for τ1 = 82 μs, τ1 = 100 μs and τ1 = 50 μs at 299°K. The value of τ1D was found to be independent of τ1. At 335°K we found τ1D to be much longer than at room temperature. The values of τ1D at 299 K, 314 K and 335 K are, respectively, 0.7 ms, 1.2 ms and 1.8 ms. From the data we estimate an activation energy for microscopic motion to be ∼ 0.2 eV.

Doping Dependence of Local Hydrogen Motion in Hydrogenated Amorphous Silicon

1993 ◽  
Vol 297 ◽  
Author(s):  
P. Hari ◽  
P.C. Taylor ◽  
R.A. Street
Keyword(s):  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Local Motion ◽  
Rf Pulses ◽  
Spin Lattice ◽  
H Nmr ◽  
Boron Doped ◽  
Hydrogenated Amorphous ◽  
Diffusion Of Hydrogen

1H NMR dipolar echo measurements have been performed on a series of samples of phosphorus- and boron-doped a-Si:H. The dipolar echo sequence consists of three rf pulses followed by an echo in the form: (π/2)x - τ1 - (π /4)y - π2- (π /4)y - echo. The echo height is plotted against π2 and the slope yields the dipolar spin-lattice relaxation time (T1D). T1D is a measure of fluctuations in the local dipolar field surrounding each hydrogen atom in a-Si:H, and measurement of this quantity can be employed as a probe of hydrogen motion on a microscopic scale. The T1D measurements of 10-5 B-doped, 10-3 P-doped and undoped a-Si:H are compared to the previously measured T1D of 10-4 B-doped a-Si:H. The T1D values for 10-4B-doped, 10-4 B-doped and undoped a-Si:H are, respectively, 1.7 ms, 11 ms and 22 ms at 300 K. The T1D for 10-3 P-doped is found to be the same as for 10-5 B-doped within experimental error. These trends are similar to the variation of the macroscopic diffusion of hydrogen with respect to various doping levels, but the details of the local motion are very different from those of the macroscopic diffusion.

NUCLEAR SPIN-LATTICE RELAXATION TIME IN TIN

1978 ◽  
Vol 39 (C6) ◽  
pp. C6-1215-C6-1216
Author(s):  
H. Ahola ◽  
G.J. Ehnholm ◽  
S.T. Islander ◽  
B. Rantala
Keyword(s):  
Relaxation Time ◽  
Nuclear Spin ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Spin Lattice Relaxation Time ◽  
Spin Lattice ◽  
Nuclear Spin Lattice Relaxation
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