scholarly journals Hole Drift-Mobility Measurements in Contemporary Amorphous Silicon

2003 ◽  
Vol 762 ◽  
Author(s):  
S. Dinca ◽  
G. Ganguly ◽  
Z. Lu ◽  
E. A. Schiff ◽  
V. Vlahos ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Valence Band ◽  
Displacement Field ◽  
Room Temperature ◽  
Hydrogenated Amorphous Silicon ◽  
Hole Mobility ◽  
Drift Mobility ◽  
Temperature Dependent ◽  
Hydrogenated Amorphous ◽  
Insight Into

AbstractWe present hole drift-mobility measurements on hydrogenated amorphous silicon from several laboratories. These temperature-dependent measurements show significant variations of the hole mobility for the differing samples. Under standard conditions (displacement/field ratio of 2×10-9 cm2/V), hole mobilities reach values as large as 0.01 cm2/Vs at room-temperature; these values are improved about tenfold over drift-mobilities of materials made a decade or so ago. The improvement is due partly to narrowing of the exponential bandtail of the valence band, but there is presently little other insight into how deposition procedures affect the hole drift-mobility.

scholarly journals Temperature-Dependent Open-Circuit Voltage Measurements and Light-Soaking in Hydrogenated Amorphous Silcon Solar Cells

2005 ◽  
Vol 862 ◽  
Author(s):  
Jianjun Liang ◽  
E. A. Schiff ◽  
S. Guha ◽  
B. Yan ◽  
J. Yang
Keyword(s):  
Solar Cells ◽  
Amorphous Silicon ◽  
Room Temperature ◽  
Open Circuit Voltage ◽  
Hydrogenated Amorphous Silicon ◽  
Open Circuit ◽  
Illumination Intensity ◽  
Temperature Dependent ◽  
Defect Generation ◽  
Hydrogenated Amorphous

AbstractWe present temperature-dependent measurements of the open-circuit voltage VOC(T) in hydrogenated amorphous silicon nip solar cells prepared at United Solar. At room-temperature and above, VOC measured using near-solar illumination intensity differs by as much as 0.04 V for the as-deposited and light-soaked states; the values of VOC for the two states converge below 250 K. Models for VOC based entirely on recombination through deep levels (dangling bonds) do not account for the convergence effect. The convergence is present in a model that assumes the recombination traffic in the as-deposited state involves only bandtails, but which splits the recombination traffic fairly evenly between bandtails and defects for the light-soaked state at room-temperature. Recombination mechanisms are important in understanding light-soaking, and the present results are inconsistent with at least one well-known model for defect generation.

scholarly journals Carrier drift-mobilities and solar cell models for amorphous and nanocrystalline silicon

2009 ◽  
Vol 1153 ◽  
Author(s):  
Eric A Schiff
Keyword(s):  
Power Generation ◽  
Solar Cells ◽  
Room Temperature ◽  
Hydrogenated Amorphous Silicon ◽  
Hole Mobility ◽  
Nanocrystalline Silicon ◽  
Drift Mobility ◽  
Cell Models ◽  
Hydrogenated Amorphous ◽  
Low Drift

AbstractHole drift mobilities in hydrogenated amorphous silicon (a-Si:H) and nanocrystalline silicon (nc-Si:H) are in the range of 10-3 to 1 cm2/Vs at room-temperature. These low drift mobilities establish corresponding hole mobility limits to the power generation and useful thicknesses of the solar cells. The properties of as-deposited a-Si:H nip solar cells are close to their hole mobility limit, but the corresponding limit has not been examined for nc-Si:H solar cells. We explore the predictions for nc-Si:H solar cells based on parameters and values estimated from hole drift-mobility and related measurements. The indicate that the hole mobility limit for nc-Si:H cells corresponds to an optimum intrinsic-layer thickness of 2-3 μm, whereas the best nc-Si:H solar cells (10% conversion efficiency) have thicknesses around 2 μm.

1 / f Noise in Hydrogenated Amorphous Silicon

1991 ◽  
Vol 219 ◽  
Author(s):  
C. Parman ◽  
J. Kakalios
Keyword(s):  
Amorphous Silicon ◽  
Power Law ◽  
Room Temperature ◽  
Hydrogenated Amorphous Silicon ◽  
Current Fluctuations ◽  
Surprising Result ◽  
Frequency Range ◽  
Temperature Dependent ◽  
Power Law Exponent ◽  
Hydrogenated Amorphous

ABSTRACTMeasurements of co-planar current fluctuations in n-type doped hydrogenated amorphous silicon (a-Si:H) find that the spectral density of the noise accurately obeys a 1/f frequency dependence over the frequency range of 1 Hz to 1 kHz for temperatures ranging from room temperature to 450K. The noise displays a power law dependence on the d.c. curent passing through the sample, with a temperature dependent power law exponent. In addition, the resistance of the a-Si:H as a function of time displays switching phenomena; a surprising result given the effective volume ( ∼10-6 cm3) of the sample.

Room-temperature electroluminescence of Er-doped hydrogenated amorphous silicon

1998 ◽  
Vol 227-230 ◽  
pp. 1164-1167 ◽  
Author(s):  
Oleg Gusev ◽  
Mikhail Bresler ◽  
Alexey Kuznetsov ◽  
Vera Kudoyarova ◽  
Petr Pak ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Room Temperature ◽  
Hydrogenated Amorphous Silicon ◽  
Er Doped ◽  
Hydrogenated Amorphous

The Spectral Dependence of the Non-Radiative Efficiency in Hydrogenated Amorphous Silicon

1992 ◽  
Vol 258 ◽  
Author(s):  
J. Fan ◽  
J. Kakalios
Keyword(s):  
Amorphous Silicon ◽  
Room Temperature ◽  
Hydrogenated Amorphous Silicon ◽  
Free Carrier ◽  
Radiative Efficiency ◽  
Sharp Minimum ◽  
Carrier Thermalization ◽  
Hydrogenated Amorphous ◽  
Kinetics Of ◽  
Heat Released

ABSTRACTThe room temperature non-radiative efficiency, defined as the ratio of the heat released per absorbed photon for doped and undoped hydrogenated amorphous silicon (a-Si:H) has been measured using photo-pyroelectric spectroscopy (PPES) for photon energies ranging from 2.5 to 1.6 eV. There is a fairly sharp minimum in the non-radiative efficiency when the a-Si:H is illuminated with near bandgap photons. We describe a model wherein this minimum arises from the variation in the amount of heat generated by free carrier thermalization as the incident photon energy is varied, and report measurements of the excitation kinetics of the non-radiative efficiency which support this proposal.

Direct Measurement of the Mobiuty-Lifetime Product of Holes and Electrons in an Amorphous Silicon P-I-N Cell

1989 ◽  
Vol 149 ◽  
Author(s):  
Richard. S. Crandall ◽  
Kyle Sadlon ◽  
Jeffrey Kalina ◽  
Alan E. Delahoy
Keyword(s):  
Amorphous Silicon ◽  
Field Model ◽  
Hydrogenated Amorphous Silicon ◽  
Hole Mobility ◽  
Charge Collection ◽  
Uniform Field ◽  
Drift Length ◽  
Direct Measurements ◽  
Hydrogenated Amorphous ◽  
Photovoltaic Behavior

ABSTRACTDirect measurements of the electron and hole mobility-lifetime products, μτ, on a 10μm thick hydrogenated amorphous silicon (a-Si:H) pi- n solar cell are presented. The μτ products, determined from charge collection using strongly absorbed light are μτ|h = 2.2 × 10−8cm2V−1 and μτ|e = 3.0 × 10−7cm2V−1, for holes,and electrons, respectively. Measurements of the drift length, ld = μτ|e + μτ|h, using uniformly absorbed light and analyzed using the uniform field model,1 give ld = 2.9 × 10−7 cm2 V−1 s−1. These results are the first experimental evidence that the carrier with the larger, μτ product determines the photovoltaic behavior. Evidence for space charge limited transport of photogenerated holes is also be presented.

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