Control of Single-Electron Charging of Metallic Nanoparticles onto Amorphous Silicon Surface

2008 ◽  
Vol 8 (11) ◽  
pp. 5684-5689 ◽  
Author(s):  
Martin Weis ◽  
Katarína Gmucová ◽  
Vojtech Nádaždy ◽  
Ignác Capek ◽  
Alexander Šatka ◽  
...  
Keyword(s):  
Electric Field ◽  
Amorphous Silicon ◽  
Double Layer ◽  
Metallic Nanoparticles ◽  
Weak Link ◽  
Silicon Film ◽  
Silicon Layer ◽  
Surface Region ◽  
Single Electron ◽  
Simultaneous Application

Sequential single-electron charging of iron oxide nanoparticles encapsulated in oleic acid/oleyl amine envelope and deposited by the Langmuir-Blodgett technique onto Pt electrode covered with undoped hydrogenated amorphous silicon film is reported. Single-electron charging (so-called quantized double-layer charging) of nanoparticles is detected by cyclic voltammetry as current peaks and the charging effect can be switched on/off by the electric field in the surface region induced by the excess of negative/positive charged defect states in the amorphous silicon layer. The particular charge states in amorphous silicon are created by the simultaneous application of a suitable bias voltage and illumination before the measurement. The influence of charged states on the electric field in the surface region is evaluated by the finite element method. The single-electron charging is analyzed by the standard quantized double layer model as well as two weak-link junctions model. Both approaches are in accordance with experiment and confirm single-electron charging by tunnelling process at room temperature. This experiment illustrates the possibility of the creation of a voltage-controlled capacitor for nanotechnology.

scholarly journals Improving the Microstructure and Electrical Properties of Aluminum Induced Polysilicon Thin Films Using Silicon Nitride Capping Layer

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Min-Hang Weng ◽  
Cheng-Tang Pan ◽  
Chien-Wei Huang ◽  
Ru-Yuan Yang
Keyword(s):  
Silicon Nitride ◽  
Electrical Properties ◽  
Amorphous Silicon ◽  
Grain Growth ◽  
Silicon Film ◽  
Silicon Layer ◽  
Optical Microscope ◽  
Dark Conductivity ◽  
Capping Layer ◽  
Short Annealing

We investigated the capping layer effect of SiNx(silicon nitride) on the microstructure, electrical, and optical properties of poly-Si (polycrystalline silicon) prepared by aluminum induced crystallization (AIC). The primary multilayer structure comprised Al (30 nm)/SiNx(20 nm)/a-Si (amorphous silicon) layer (100 nm)/ITO coated glass and was then annealed in a low annealing temperature of 350°C with different annealing times, 15, 30, 45, and 60 min. The crystallization properties were analyzed and verified by X-ray diffraction (XRD) and Raman spectra. The grain growth was analyzed via optical microscope (OM) and scanning electron microscopy (SEM). The improved electrical properties such as Hall mobility, resistivity, and dark conductivity were investigated by using Hall and current-voltage (I-V) measurements. The results show that the amorphous silicon film has been effectively induced even at a low temperature of 350°C and a short annealing time of 15 min and indicate that the SiNxcapping layer can improve the grain growth and reduce the metal content in the induced poly-Si film. It is found that the large grain size is over 20 μm and the carrier mobility values are over 80 cm2/V-s.

Nano-Indentation for Measurement on Mechanical Property of Building Integrated Amorphous Silicon Thin-Film PV Cell

2014 ◽  
Vol 638-640 ◽  
pp. 1365-1368
Author(s):  
Shun Mei Li ◽  
Jun Mei ◽  
Yu Liu ◽  
Yong Yao ◽  
Lin Gang Lan ◽  
...  
Keyword(s):  
Thin Film ◽  
Elastic Modulus ◽  
Amorphous Silicon ◽  
Loading Rate ◽  
Silicon Film ◽  
Peak Load ◽  
Silicon Layer ◽  
Silicon Thin Film ◽  
Testing Method ◽  
Pv Cell

Amorphous silicon thin-film PV cell(AST) generally consists of a few – micron thick silicon film on a glass substrate, which has difficulty for being accurately measured by using a conventional testing method to obtain its elastic modulus and hardness. In our study, we are applying nanoindentation for the measurement purpose and divide the sample into five regions for studying. Both of peak load - and loading rate - dependences supervise us to more accurately measure the mechanical properties of silicon layer through defining the peak load at 9000μN and loading rate at 1000μN/s. It was also observed that across the whole sample measurements on the elastic modulus have much better consistence than those on the hardness. We therefore propose a method of partitioning the sample into two parts for counting the different hardness measurements.

Nickel Induced Lateral Crystallization of Amorphous Silicon Film by Electroless Planting

2009 ◽  
Vol 66 ◽  
pp. 147-150
Author(s):  
Wei Li ◽  
Dong Lin Xia ◽  
Ming Xia Song ◽  
Zhen Zhong Zhang ◽  
Jia Miao Ni ◽  
...  
Keyword(s):  
Electric Field ◽  
Amorphous Silicon ◽  
Silicon Film ◽  
Electroless Nickel ◽  
Nitrogen Atmosphere ◽  
Nickel Film ◽  
Glass Substrates ◽  
Amorphous Silicon Film ◽  
Lateral Crystallization ◽  
Nickel Distribution

A novel deposition way of nickel film for crystallization amorphous silicon film is introduced. Electroless nickel planting is a convenient and inexpensive way to deposit nickel without using the electric field or any large facility. A 200 nm nickel film is deposited on the glass substrates and then a 300nm a-Si film is deposited on the nickel film with a horizontal electric field assisted to enhance amorphous silicon crystallization. The bi-layer film is annealed at 500°C for several hours in the nitrogen atmosphere. The crystallized Si thin films were characterized by Raman spectroscopy, Field emission scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The Raman demonstrates that the a-Si has been crystallized. Furthermore the FE-SEM shows the lateral crystalline morphology, the length of grain is up to 5µm and the EDS reveals the nickel distribution in the MILC and MIC area.

scholarly journals Electric Field Distribution in Hybrid Solar Cells Comprising an Organic Donor Polymer and Amorphous Silicon

2014 ◽  
Vol 2 (1) ◽  
Author(s):  
S. Schaefer ◽  
S. Albrecht ◽  
D. Neher ◽  
T. F. Schulze ◽  
E. Conrad ◽  
...  
Keyword(s):  
Solar Cells ◽  
Electric Field ◽  
Amorphous Silicon ◽  
Field Distribution ◽  
Organic Material ◽  
Electric Field Distribution ◽  
Layer Structure ◽  
Short Circuit ◽  
Silicon Layer ◽  
Hybrid Solar Cells

AbstractWe present a study on the performance and analysis of hybrid solar cells comprising a planar heterojunction between between a conjugated donor polymer, P3HT or PCPDTBT, and hydrogenated amorphous silicon (a-Si:H). A comparison of the modeled absorption spectra of the layer stack with the measured external quantum efficiency is used to investigate the contribution of the inorganic and organic material to the photocurrent generation in the device. Although both materials contribute to the photocurrent, the devices exhibit poor quantum efficiencies and low short circuit currents. Bandstructure simulations of the hybrid layer structure reveal that an unfavorable electric field distribution within the planar multilayer structure limits the performance. Using electroabsorption measurements we can show that the electric field is extremelyweak in the amorphous silicon but strong in the organic material. The situation changes drasticallywhen the conjugated polymer is p-doped. Doping not only increases the conductivity of the organic material, but also restores the electric field in the amorphous silicon layer. Optimized hybrid solar cells comprising thin doped P3HT layers exhibit energy conversion efficiencies (ECE) up to 2.8 %.

Photo and Thermal Stability of Chlorine Doped Amorphous Silicon TFTs

1997 ◽  
Vol 471 ◽  
Author(s):  
J. H. Kim ◽  
J. H. Choi ◽  
C. W. Kim ◽  
J. H. Souk
Keyword(s):  
Thermal Stability ◽  
Amorphous Silicon ◽  
Double Layer ◽  
Flow Rate ◽  
High Stability ◽  
Elevated Temperatures ◽  
Silicon Film ◽  
Gas Mixture ◽  
Amorphous Silicon Film ◽  
Thermal Stability Of

ABSTRACTThe Cl doped amorphous silicon film was deposited from SiH4, SiH2C12 and H2 gas mixture by PECVD process and their properties with various SiH2C12 flow rate is discussed. Controlling the amount of Cl doped was crucial for acquiring high stability TFT without lowering on current. Amorphous silicon and Cl doped amorphous silicon double layer TFT structure, with satisfactory on current and throughput, proved to be more stable than conventional amorphous silicon TFT in photo state and in elevated temperatures.

Modeling the Electrical Double Layer to Understand the Reaction Environment in a CO2 Electrocatalytic System

2019 ◽  
Author(s):  
Divya Bohra ◽  
Jehanzeb Chaudhry ◽  
Thomas Burdyny ◽  
Evgeny Pidko ◽  
wilson smith
Keyword(s):  
Electric Field ◽  
Double Layer ◽  
Electrical Double Layer ◽  
Surface Reaction ◽  
Catalyst Surface ◽  
Local Reaction ◽  
Reaction Diffusion ◽  
Alkali Metal Cations ◽  
Applied Potential ◽  
Critical Aspect

<p>The environment of a CO<sub>2</sub> electroreduction (CO<sub>2</sub>ER) catalyst is intimately coupled with the surface reaction energetics and is therefore a critical aspect of the overall system performance. The immediate reaction environment of the electrocatalyst constitutes the electrical double layer (EDL) which extends a few nanometers into the electrolyte and screens the surface charge density. In this study, we resolve the species concentrations and potential profiles in the EDL of a CO<sub>2</sub>ER system by self-consistently solving the migration, diffusion and reaction phenomena using the generalized modified Poisson-Nernst-Planck (GMPNP) equations which include the effect of volume exclusion due to the solvated size of solution species. We demonstrate that the concentration of solvated cations builds at the outer Helmholtz plane (OHP) with increasing applied potential until the steric limit is reached. The formation of the EDL is expected to have important consequences for the transport of the CO<sub>2</sub> molecule to the catalyst surface. The electric field in the EDL diminishes the pH in the first 5 nm from the OHP, with an accumulation of protons and a concomitant depletion of hydroxide ions. This is a considerable departure from the results obtained using reaction-diffusion models where migration is ignored. Finally, we use the GMPNP model to compare the nature of the EDL for different alkali metal cations to show the effect of solvated size and polarization of water on the resultant electric field. Our results establish the significance of the EDL and electrostatic forces in defining the local reaction environment of CO<sub>2</sub> electrocatalysts.</p>

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