Conduction mechanisms in doped mixed-phase hydrogenated amorphous/nanocrystalline silicon thin films

2013 ◽  
Vol 113 (23) ◽  
pp. 233707 ◽  
Author(s):  
L. R. Wienkes ◽  
C. Blackwell ◽  
T. Hutchinson ◽  
J. Kakalios
Keyword(s):  
Thin Films ◽  
Nanocrystalline Silicon ◽  
Mixed Phase ◽  
Silicon Thin Films ◽  
Conduction Mechanisms ◽  
Hydrogenated Amorphous

Thermoelectric properties of doped and undoped mixed phase hydrogenated amorphous/nanocrystalline silicon thin films

2010 ◽  
Vol 1245 ◽  
Author(s):  
James Kakalios ◽  
Yves Adjallah ◽  
Charlie Blackwell
Keyword(s):  
Thin Films ◽  
Seebeck Coefficient ◽  
Temperature Dependence ◽  
Nanocrystalline Silicon ◽  
Dark Conductivity ◽  
Mixed Phase ◽  
Positive Temperature ◽  
Silicon Thin Films ◽  
Similar Temperature Dependence ◽  
Hydrogenated Amorphous

AbstractThe Seebeck coefficient and dark conductivity for undoped, and n-type doped thin film hydrogenated amorphous silicon (a-Si:H), and mixed-phase films with silicon nanocrystalline inclusions (a/nc-Si:H) are reported. For both undoped a-Si:H and undoped a/nc-Si:H films, the dark conductivity is enhanced by the addition of silicon nanocrystals. The thermopower of the undoped a/nc-Si:H has a lower Seebeck coefficient, and similar temperature dependence, to that observed for undoped a-Si:H. In contrast, the addition of nanoparticles in doped a/nc-Si:H thin films leads to a negative Seebeck coefficient (consistent with n-type doping) with a positive temperature dependence, that is, the Seebeck coefficient becomes larger at higher temperatures. The temperature dependence of the thermopower of the doped a/nc-Si:H is similar to that observed in unhydrogenated a-Si grown by sputtering or following high-temperature annealing of a-Si:H, suggesting that charge transport may occur via hopping in these materials.

Growth of Mixed-Phase Amorphous and Ultra Nanocrystalline Silicon Thin Films in the Low Pressure Regime by a VHF PECVD Process

Silicon ◽  
2012 ◽  
Vol 4 (2) ◽  
pp. 127-135 ◽  
Author(s):  
Jhuma Gope ◽  
Sushil Kumar ◽  
Sukhbir Singh ◽  
C. M. S. Rauthan ◽  
P. C. Srivastava
Keyword(s):  
Thin Films ◽  
Nanocrystalline Silicon ◽  
Low Pressure ◽  
Mixed Phase ◽  
Silicon Thin Films ◽  
Pressure Regime

HYDROGENATED AMORPHOUS/NANOCRYSTALLINE SILICON THIN FILMS ON POROUS ANODIC ALUMINA SUBSTRATE

2010 ◽  
Vol 17 (03) ◽  
pp. 283-288 ◽  
Author(s):  
SANG-OK KIM ◽  
ALIAKSANDR KHODIN ◽  
JOONG KEE LEE
Keyword(s):  
Thin Films ◽  
Electron Cyclotron Resonance ◽  
Chemical Vapor ◽  
Nanocrystalline Silicon ◽  
Anodic Alumina ◽  
Porous Anodic Alumina ◽  
Textured Surfaces ◽  
Silicon Thin Films ◽  
Vapor Deposition Technique ◽  
Hydrogenated Amorphous

Hydrogenated amorphous and nanocrystalline silicon thin films were grown on porous anodic alumina substrates using electron cyclotron resonance-chemical vapor deposition technique from argon, hydrogen and silane gas composition. The structural characterization of the deposited hydrogenated silicon films were performed by scanning electron microscopy, Raman spectroscopy, and X-ray diffraction studies. The results revealed that mixed amorphous/nanocrystalline silicon phases with specific novel morphology were obtained on textured surfaces. The evolution of the film on ripple-like surface exhibited amorphous dominant structure, however, the film deposited on tipped/ribbed surface consisted of amorphous and nanocrystalline phases composite. The growth process strongly depends on the textured substrate pattern, which influences on the nanostructure shapes and crystallinity.

Hydrogenated Amorphous Silicon Thin Films with Nanocrystalline Silicon Inclusions

2003 ◽  
Vol 762 ◽  
Author(s):  
T. J. Belich ◽  
S. Thompson ◽  
C.R. Perrey ◽  
U. Kortshagen ◽  
C.B. Carter ◽  
...  
Keyword(s):  
Thin Films ◽  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Nanocrystalline Silicon ◽  
Dark Conductivity ◽  
Capacitively Coupled ◽  
Silicon Thin Films ◽  
High Resolution Tem ◽  
Hydrogenated Amorphous ◽  
Deposition Conditions

AbstractThin films of hydrogenated amorphous silicon containing nanocrystalline silicon inclusions (a/nc-Si:H) have been synthesized in an RF capacitively coupled PECVD system using a mixture of hydrogen diluted silane and helium, under deposition conditions at the edge of powder formation within the plasma. High resolution TEM confirms the presence of nanocrystallites as small as 2 nm in these films. Measurements of the optical absorption spectrum using CPM and PDS indicates a broadening of the Urbach slope in the a/nc-Si:H, compared to a-Si:H films, but no appreciable increase in midgap absorption. Despite the deposition conditions for the a/nc-Si:H being very different from those associated with producing optimal quality a-Si:H, the dark conductivity and photoconductivity values, and the sensitivity to light-induced defect creation in the a/nc-Si:H films are comparable to those in a-Si:H.

Electronic Transport in Co-deposited Hydrogenated Amorphous/Nanocrystalline Thin Films

2008 ◽  
Vol 1066 ◽  
Author(s):  
Y. Adjallah ◽  
C. Blackwell ◽  
C. Anderson ◽  
U. Kortshagen ◽  
J. Kakalios
Keyword(s):  
Thin Films ◽  
Amorphous Silicon ◽  
Volume Fraction ◽  
Crystalline Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Nanocrystalline Silicon ◽  
Dark Conductivity ◽  
Mixed Phase ◽  
Bonding Structure ◽  
Hydrogenated Amorphous

ABSTRACTMixed-phase hydrogenated amorphous silicon thin films containing nanocrystalline silicon inclusions have been synthesized in a dual chamber co-deposition system. A PECVD deposition system produces small crystalline silicon particles (3-5 nm diameter) in a flow-through reactor, and injects these particles into a separate capacitively-coupled plasma chamber in which hydrogenated amorphous silicon is deposited. Raman spectroscopy is used to determine the volume fraction of nanocrystals in the mixed phase thin films, while infra-red spectroscopy characterizes the hydrogen bonding structure as a function of nanocrystalline concentration. At a moderate concentration of 5 nm silicon crystallites, the dark conductivity and photoconductivity are consistently found to be higher than in mixed phase films with either lower or higher densities of nanocrystalline inclusions.

Sign in / Sign up

Export Citation Format

Share Document