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.

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 Hole Drift Mobility Measurements on a-Si:H using Surface and Uniformly Absorbed Illumination

2009 ◽  
Vol 1153 ◽  
Author(s):  
Steluta Adriana Dinca ◽  
Eric A Schiff ◽  
Subhendu Guha ◽  
Baojie Yan ◽  
Jeff Yang
Keyword(s):  
Stainless Steel ◽  
Solar Cells ◽  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Time Of Flight ◽  
Drift Mobility ◽  
Electrode Interface ◽  
Steel Substrates ◽  
Hydrogenated Amorphous ◽  
Time Of Flight Method

AbstractThe standard, time-of-flight method for measuring drift mobilities in semiconductors uses strongly absorbed illumination to create a sheet of photocarriers near an electrode interface. This method is problematic for solar cells deposited onto opaque substrates, and in particular cannot be used for hole photocarriers in hydrogenated amorphous silicon (a Si:H) solar cells using stainless steel substrates. In this paper we report on the extension of the time-of-flight method that uses weakly absorbed illumination. We measured hole drift-mobilities on seven a Si:H nip solar cells using strongly and weakly absorbed illumination incident through the n-layer. For thinner devices from two laboratories, the drift-mobilities agreed with each other to within our random error of about 15%. For thicker devices from United Solar, the drift-mobilities were about twice as large when measured using strongly absorbed illumination. We propose that this effect is due to a mobility profile in the intrinsic absorber layer in which the mobility decreases for increasing distance from the substrate.

scholarly journals Enhanced Photoelectrical Response of Hydrogenated Amorphous Silicon Single-Nanowire Solar Cells by Front-Opening Crescent Design

2016 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhenhai Yang ◽  
Guoyang Cao ◽  
Aixue Shang ◽  
Dang Yuan Lei ◽  
Cheng Zhang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Single Nanowire ◽  
Hydrogenated Amorphous

Hydrogenated Nanocrystalline Silicon Thin Film Transistor Array for X-ray Detector Application

2008 ◽  
Vol 1066 ◽  
Author(s):  
Kyung-Wook Shin ◽  
Mohammad R. Esmaeili-Rad ◽  
Andrei Sazonov ◽  
Arokia Nathan
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Threshold Voltage ◽  
Hydrogenated Amorphous Silicon ◽  
Nanocrystalline Silicon ◽  
Amorphous Selenium ◽  
Breakdown Field ◽  
Storage Capacitor ◽  
X Ray ◽  
Hydrogenated Amorphous

ABSTRACTHydrogenated nanocrystalline silicon (nc-Si:H) has strong potential to replace the hydrogenated amorphous silicon (a-Si:H) in thin film transistors (TFTs) due to its compatibility with the current industrial a-Si:H processes, and its better threshold voltage stability [1]. In this paper, we present an experimental TFT array backplane for direct conversion X-ray detector, using inverted staggered bottom gate nc-Si:H TFT as switching element. The TFTs employed a nc-Si:H/a-Si:H bilayer as the channel layer and hydrogenated amorphous silicon nitride (a-SiNx) as the gate dielectric; both layers deposited by plasma enhanced chemical vapor deposition (PECVD) at 280°C. Each pixel consists of a switching TFT, a charge storage capacitor (Cpx), and a mushroom electrode which serves as the bottom contact for X-ray detector such as amorphous selenium photoconductor. The chemical composition of the a-SiNx was studied by Fourier transform infrared spectroscopy. Current-voltage measurements of the a-SiNx film demonstrate that a breakdown field of 4.3 MV/cm.. TFTs in the array exhibits a field effect mobility (μEF) of 0.15 cm2/V·s, a threshold voltage (VTh) of 5.71 V, and a subthreshold leakage current (Isub) of 10−10 A. The fabrication sequence and TFT characteristics will be discussed in details.

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.

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