A slow positron lifetime study of the annealing behaviour of an amorphous silicon layer grown by MBE

1995 ◽  
Vol 61 (1) ◽  
pp. 71-74
Author(s):  
J. St�rmer ◽  
P. Willutzki ◽  
D. T. Britton ◽  
G. K�gel ◽  
W. Triftsh�user ◽  
...  
1995 ◽  
Vol 61 (1) ◽  
pp. 71-74 ◽  
Author(s):  
J. St�rmer ◽  
P. Willutzki ◽  
D. T. Britton ◽  
G. K�gel ◽  
W. Triftsh�user ◽  
...  

1992 ◽  
Vol 262 ◽  
Author(s):  
H. Kametani ◽  
H. Akiyama ◽  
Y. Yamaguchi ◽  
M. Koumaru ◽  
L. Wei ◽  
...  

ABSTRACTSlow/monoenergetic positron beams and pulsed positron beams have been used as a non-destructive probe to investigate vacancy-type defects in SIMOX substrates which were formed by high - dose oxygen implantation and high-temperature annealing. To obtain depth profiles of vacancy-type defects, a positron beam in the 0–30keV energy range was used. Doppler broadened annihilation spectrum and positron lifetime were measured as a function of incident positron energy. These measurements show the following results; vacancy -type defects exist near the surface of the top silicon layer even if the specimen was analyzed as defect -free Silicon by XTEM, and in the case of the as-implanted specimen, cavities in diameter of about 50–200A are created in the top silicon layer and they include high pressure gases.


2015 ◽  
Vol 1770 ◽  
pp. 7-12 ◽  
Author(s):  
Henriette A. Gatz ◽  
Yinghuan Kuang ◽  
Marcel A. Verheijen ◽  
Jatin K. Rath ◽  
Wilhelmus M.M. (Erwin) Kessels ◽  
...  

ABSTRACTSilicon heterojunction solar cells (SHJ) with thin intrinsic layers are well known for their high efficiencies. A promising way to further enhance their excellent characteristics is to enable more light to enter the crystalline silicon (c-Si) absorber of the cell while maintaining a simple cell configuration. Our approach is to replace the amorphous silicon (a-Si:H) emitter layer with a more transparent nanocrystalline silicon oxide (nc-SiOx:H) layer. In this work, we focus on optimizing the p-type nc-SiOx:H material properties, grown by radio frequency plasma enhanced chemical vapor deposition (rf PECVD), on an amorphous silicon layer.20 nm thick nanocrystalline layers were successfully grown on a 5 nm a-Si:H layer. The effect of different ratios of trimethylboron to silane gas flow rates on the material properties were investigated, yielding an optimized material with a conductivity in the lateral direction of 7.9×10-4 S/cm combined with a band gap of E04 = 2.33 eV. Despite its larger thickness as compared to a conventional window a-Si:H p-layer, the novel layer stack of a-Si:H(i)/nc-SiOx:H(p) shows significantly enhanced transmission compared to the stack with a conventional a-Si:H(p) emitter. Altogether, the chosen material exhibits promising characteristics for implementation in SHJ solar cells.


2007 ◽  
Vol 124-126 ◽  
pp. 259-262
Author(s):  
Jae Hong Jeon ◽  
Kang Woong Lee

We investigated the effect of amorphous silicon pattern design regarding to light induced leakage current in amorphous silicon thin film transistor. In addition to conventional design, where amorphous silicon layer is protruding outside the gate electrode, we designed and fabricated amorphous silicon thin film transistors in another two types of bottom gated structure. The one is that the amorphous silicon layer is located completely inside the gate electrode and the other is that the amorphous silicon layer is protruding outside the gate electrode but covered completely by the source and drain electrode. Measurement of the light induced leakage current caused by backlight revealed that the design where the amorphous silicon is located inside the gate electrode was the most effective however the last design was also effective in reducing the leakage current about one order lower than that of the conventional design.


1992 ◽  
Vol 12 (1-2) ◽  
pp. 103-106 ◽  
Author(s):  
Yu.N. Erokhin ◽  
R. Grötzschel ◽  
S.R. Oktyabrsky ◽  
S. Roorda ◽  
W. Sinke ◽  
...  

1999 ◽  
Vol 5 (S2) ◽  
pp. 754-755
Author(s):  
Lawrence K Lam ◽  
Nan Jiang ◽  
Dieter G Ast ◽  
John Silcox

Recently there has been increasing interest in nickel induced lateral recrystallization of amorphous silicon because of its potential to improve device performance and to lower the thermal budget during processing. The hypothesis is that the formation of nickel silicide provides a low energy nucleus for the recrystallization of amorphous silicon. The silicide, moving into a-Si, leaves crystalline silicon behind.1 The grains formed, therefore, tend to elongated. In this paper, we attempt to use TEM to investigate in detail the nickel assisted lateral crystallization of amorphous silicon. The sample was prepared by first depositing a 1000A thick low temperature, oxide layer, LTO, on Corning 1737 glass. A 1000A thick amorphous silicon layer, a-Si, and 1000A thick a-Si were deposited subsequently. The sample was pattern and etched with hydrofluoric acid to form lOum x lOum holes in the oxide layer. Next, 200A of nickel was evaporated onto the sample, followed by a 600°C, 6 hours anneal to induce lateral recrystallization.


1982 ◽  
Vol 18 ◽  
Author(s):  
S. R. Herd ◽  
K. Y. Ahn ◽  
K. N. Tu

We investigated the interaction of extremely thin (less than 10 nm) crystalline gold and rhodium films with amorphous silicon by transmission electron microscope in situ annealing. In thin Au/Si bilayers an amorphous phase with a diffraction peak at d ≂ 0.226 nm is formed by thermal annealing between 150 and 200 °C. Depending on the thickness and composition, silicon sputtered onto thin gold films leads to the formation of a layer of amorphous silicon and a partially amorphous Au-Si layer during deposition. The silicon layer crystallizes by itself at temperatures as low as 150 °C, and at 300 °C the amorphous Au–Si layer crystallizes into a metastable gold silicide (for silicon-rich compositions). In Rh/Si bilayers an amorphous Rh–Si phase is formed by annealing to 300 °C and can be detected by electron diffraction for a rhodium thickness of less than 5 nm and compositions with more than 50% Si if completely reacted. Above 300 °C the amorphous Rh-Si crystallizes preferentially in the cubic form of RhSi for intermediate silicon compositions and in the orthorhombic form of RhSi for high silicon compositions. Excess amorphous silicon is not found to have a lowered crystallization temperature when in contact with the amorphous Rh-Si alloy, and crystalline silicon is only observed above 730 °C together with the cubic and/or orthorhombic RhSi. In Rh/Si bilayers with a thicker rhodium layer, no formation of an amorphous phase was observed on annealing; instead crystalline Rh2Si forms during annealing above 300 °C.


2010 ◽  
Vol 1245 ◽  
Author(s):  
Rudi Santbergen ◽  
Renrong Liang ◽  
Miro Zeman

AbstractA novel light trapping technique for solar cells is based on light scattering by metal nanoparticles through excitation of localized surface plasmons. We investigated the effect of metal nanoparticles embedded inside the absorber layer of amorphous silicon solar cells on the cell performance. The position of the particles inside the absorber layer was varied. Transmission electron microscopy images of the cell devices showed well defined silver nanoparticles, indicating that they survive the embedding procedure. The optical absorption of samples where the silver nanoparticles were embedded in thin amorphous silicon layer showed an enhancement peak around the plasmon resonance of 800 nm. The embedded particles significantly reduce the performance of the fabricated devices. We attribute this to the recombination of photogenerated charge carriers in the absorber layer induced by the presence of the silver nanoparticles. Finally we demonstrate that the fabricated solar cells exhibit tandem-like behavior where the silver nanoparticles separate the absorber layer into a top and bottom part.


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