Capacitance Spectroscopy of Defects in a-SI:H/c-SI Heterostructures

1999 ◽  
Vol 557 ◽  
Author(s):  
M. Rösch ◽  
T. Unold ◽  
R. Pointmayer ◽  
G.H. Bauer
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Clear Correlation ◽  
Temperature Dependent ◽  
Capacitance Measurements ◽  
Interface Defects ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Capacitance Spectroscopy ◽  
Hydrogenated Amorphous

AbstractWe investigate defects at the interface in heterodiodes of hydrogenated amorphous silicon and monocrystalline silicon by frequency and temperature dependent capacitance measurements. The interpretation of the experimental results is supported by numerical simulations of capacitance experiments via transient calculations of defect charging and decharging in the diodes. A defined variation of waver surface treatments prior to amorphous silicon deposition shows a clear correlation of interface defects determined by capacitance measurements with current-voltage characteristics.

Simulation of Hydrogenated Amorphous Silicon Germanium Alloys for Bandgap Grading

1999 ◽  
Vol 557 ◽  
Author(s):  
E. Schroten ◽  
M. Zeman ◽  
R. A. C. M. M. van Swaaij ◽  
L. L. A. Vosteen ◽  
J. W. Metselaar
Keyword(s):  
Amorphous Silicon ◽  
Material Properties ◽  
Silicon Germanium ◽  
Hydrogenated Amorphous Silicon ◽  
Model Parameters ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Amorphous Silicon Germanium ◽  
Parameter Values ◽  
Hydrogenated Amorphous

AbstractComputer simulations are reported of hydrogenated amorphous silicon germanium (a-SiGe:H) layers that make up the graded part of the intrinsic layer near the interfaces of a-SiGe:H solar cells. Therefore the graded part is approached with a ‘staircase’ bandgap profile, consisting of three layers within which the material properties are constant. Calibrated model parameters are obtained by matching simulation results of material properties of intrinsic a-SiGe:H single layers to measurements. Using the obtained model parameter sets subsequent simulations of p-i-n devices with intrinsic material similar to the single layers are matched to measured current-voltage characteristics. The changes in parameter values are evaluated as a function of optical gap.

Fast light-induced change in ellipsometry spectra of hydrogenated amorphous silicon measured through a transparent substrate upon bias light illumination

2001 ◽  
Vol 664 ◽  
Author(s):  
N. Hata ◽  
C. M. Fortmann ◽  
A. Matsuda
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Light Illumination ◽  
Temperature Dependent ◽  
Transparent Substrate ◽  
Optical Effects ◽  
The Stability ◽  
Fast Light ◽  
First Time ◽  
Hydrogenated Amorphous

ABSTRACTPrevious ellipsometric studies of the stability of amorphous silicon (a-Si:H) found reversible changes in the pseudo-dielectric functions. These changes were slow to generate and slow to anneal away. These slow changes are associated with a dangling bond related structural change. Since any light-induced change in the dielectric function is useful for photonic engineering, we undertook the present more detailed study of light induced optical effects in a-Si:H. The optical pseudo-dielectric functions of hydrogenated amorphous silicon (a-Si:H) were measured using spectroscopic ellipsometry (SE) and the “through-the-substrate” measurement technique as a function of measurement temperature and bias light illumination. For the first time we report a light-induced change in a-Si:H materials that is fast, bias-light-dependent, reversible, and temperature dependent. This effect, while not completely understood, offers exciting new prospects for photonic engineering.

Low Temperature Characteristics of Hydrogenated Amorphous Silicon Field Effect Transistors

1989 ◽  
Vol 149 ◽  
Author(s):  
Byung-Seong Bae ◽  
Deok-Ho Cho ◽  
Jae-Hee Lee ◽  
Choochon Lee ◽  
Jin Jang
Keyword(s):  
Low Temperature ◽  
Amorphous Silicon ◽  
Threshold Voltage ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Hydrogenated Amorphous Silicon ◽  
Field Effect Mobility ◽  
Temperature Dependent ◽  
Hydrogenated Amorphous ◽  
Very Low Temperature

ABSTRACTWe investigated the temperature dependent characteristics of hydrogenated amorphous silicon (a-Si:H) thin film transistors (TFT's) at temperatures down to 20 K. With decreasing temperature, the threshold voltage increased, the field effect mobility and the on-current decreased. The measured on-currents versus inverse temperature above 80 K are represented as the sum of two exponentially varied currents. It is concluded that on-current is nearest-neighbour hopping between 120 K and 80 K. Below this temperature, the temperature dependence of on-current is explained by variable range hopping and below about 30 K on-current becomes nearly independent of temperature. At very low temperature hopping probability may be governed not by temperature but by temperature independent tunneling, depending on the overlap of the wave function. The explanation of threshold voltage increase at low temperature is given.

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