Application of Spectroscopic Ellipsometry and Infrared Spectroscopy for the Real-Time Control and Characterization of a-Si:H Growth in a-Si:H/c-Si Heterojunction Solar Cells

2005 ◽  
Vol 862 ◽  
Author(s):  
Hiroyuki Fujiwara ◽  
Michio Kondo
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Real Time ◽  
Spectroscopic Ellipsometry ◽  
Function Analysis ◽  
Interface Layer ◽  
Layer Growth ◽  
Attenuated Total Reflection ◽  
Real Time Control ◽  
Heterojunction Solar Cells

AbstractWe have demonstrated real-time process control of a-Si:H growth in an a-Si:H/c-Si heterojunction solar cell by spectroscopic ellipsometry (SE). Accurate thickness control of a-Si:H p-i layers with a precision better than ± Å has been realized by this technique. From real-time attenuated total reflection spectroscopy (ATR), we find the formation of a porous interface layer with a maximum SiH2-hydrogen content of 27 at.% at the a-Si:H/c-Si interface, although a rather high conversion efficiency of 14.6 % has been obtained in the solar cell. We found that an optimum i-layer thickness for the a-Si:H/c-Si solar cells is consistent with the thickness at which the a-Si:H i-layer growth reaches a steady state after the H-rich interface-layer formation. We have applied SE further to determine the dielectric functions of In2O3:Sn and ZnO:Ga with different carrier concentrations. From the dielectric function analysis, the effective mass m is extracted. We find linear increases in m as the carrier concentration of In2O3:Sn and ZnO:Ga increases. The validity of our analyses has been confirmed from excellent agreement between carrier concentrations determined by SE and Hall measurements. The construction of the optical database further enabled us to calculate a reflectance spectrum of the a-Si:H/c-Si solar cell accurately.

17.8%-efficient Amorphous Silicon Heterojunction Solar Cells on p-type Silicon Wafers

2006 ◽  
Vol 910 ◽  
Author(s):  
Qi Wang ◽  
Matt P. Page ◽  
Eugene Iwancizko ◽  
Yueqin Xu ◽  
Yanfa Yan ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Amorphous Silicon ◽  
High Efficiency ◽  
Short Circuit ◽  
Open Circuit ◽  
Layer Growth ◽  
Surface Recombination Velocity ◽  
Back Contact ◽  
P Type

AbstractWe have achieved an independently-confirmed 17.8% conversion efficiency in a 1-cm2, p-type, float-zone silicon (FZ-Si) based heterojunction solar cell. Both the front emitter and back contact are hydrogenated amorphous silicon (a-Si:H) deposited by hot-wire chemical vapor deposition (HWCVD). This is the highest reported efficiency for a HWCVD silicon heterojunction (SHJ) solar cell. Two main improvements lead to our most recent increases in efficiency: 1) the use of textured Si wafers, and 2) the application of a-Si:H heterojunctions on both sides of the cell. Despite the use of textured c-Si to increase the short-circuit current, we were able to maintain the same 0.65 V open-circuit voltage as on flat c-Si. This is achieved by coating a-Si:H conformally on the c-Si surfaces, including covering the tips of the anisotropically-etched pyramids. A brief atomic H treatment before emitter deposition is not necessary on the textured wafers, though it was helpful in the flat wafers. It is essential to high efficiency SHJ solar cells that the emitter grows abruptly as amorphous silicon, instead of as microcrystalline or epitaxial Si. The contact on each side of the cell comprises a thin (< 5 nm) low substrate temperature (~100°C) intrinsic a-Si:H layer, followed by a doped layer. Our intrinsic layers are deposited at 0.3-1.2 nm/s. The doped emitter and back-contact layers were deposited at a higher temperature (>200°C) and grown from PH3/SiH4/H2 and B2H6/SiH4/H2 doping gas mixtures, respectively. This combination of low (intrinsic) and high (doped layer) growth temperatures was optimized by lifetime and surface recombination velocity measurements. Our rapid efficiency advance suggests that HWCVD may have advantages over plasma-enhanced (PE) CVD in fabrication of high-efficiency heterojunction c-Si cells; there is no need for process optimization to avoid plasma damage to the delicate, high-quality, Si wafers.

Fabrication and characterization of CuPc and PCBM based organic solar cell with metal interlayer

2015 ◽  
Vol 12 (5) ◽  
pp. 413-420
Author(s):  
Muhammad Ahsan Naveed ◽  
A. Hussain ◽  
K. Islam ◽  
P. Akhter
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Impedance Spectroscopy ◽  
Organic Solar Cells ◽  
Organic Solar Cell ◽  
Silver Layer ◽  
Absorbance Spectrum ◽  
Heterojunction Solar Cells ◽  
Processing Cost ◽  
Donor Acceptor

Organic solar cells have potential as an alternative to conventional inorganic solar cell due to low processing cost, flexibility and easy fabrication technique. The goal of this paper is to study the characteristics of the CuPc and PCBM based organic solar cell by introducing a thin layer of Ag at the interface of donor (CuPc) and Acceptor (PCBM), their photovoltaic and optical properties were investigated. The heterojunction solar cells with and without silver inter layer were fabricated through thermal deposition in HR vacuum. The OPV solar cells were characterized using current-voltage graphs, absorbance spectrum and Impedance spectroscopy. Impedance spectroscopy was taken to identify the traps using series resistance, parallel resistance, and Impedance spectrums under different frequencies. Optical behaviors of these devices have been investigated with absorbance spectrum. Introducing Ag to interfacing point produced traps and these traps causes to decreased Voc, Isc, FF, and efficiency. The effect of silver layer at donor acceptor interface was studied.

Optimisation of diketopyrrolopyrrole:fullerene solar cell performance through control of polymer molecular weight and thermal annealing

2014 ◽  
Vol 2 (45) ◽  
pp. 19282-19289 ◽  
Author(s):  
Zhenggang Huang ◽  
Elisa Collado Fregoso ◽  
Stoichko Dimitrov ◽  
Pabitra Shakya Tuladhar ◽  
Ying Woan Soon ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Solar Cells ◽  
Solar Cell ◽  
Thermal Annealing ◽  
Bulk Heterojunction ◽  
Cell Performance ◽  
Polymer Molecular Weight ◽  
Solar Cell Performance ◽  
Heterojunction Solar Cells ◽  
Bulk Heterojunction Solar Cells

The performance of bulk heterojunction solar cells based on a novel donor polymer DPP-TT-T was optimised by tuning molecular weight and thermal annealing.

Conventional polymer solar cells with power conversion efficiencies increased to >9% by a combination of methanol treatment and an anionic conjugated polyelectrolyte interface layer

RSC Advances ◽  
2014 ◽  
Vol 4 (92) ◽  
pp. 50988-50992 ◽  
Author(s):  
Tao Yuan ◽  
Dong Yang ◽  
Xiaoguang Zhu ◽  
Lingyu Zhou ◽  
Jian Zhang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Thin Layer ◽  
Polymer Solar Cell ◽  
Polymer Solar Cells ◽  
Power Conversion ◽  
Interface Layer ◽  
Conjugated Polyelectrolyte ◽  
Methanol Treatment ◽  
Conversion Efficiencies

The power conversion efficiency of a PTB7:PC71BM polymer solar cell was improved up to 9.1% by a combination of methanol treatment followed by conjugation of a water- or alcohol-soluble polyelectrolyte thin layer.

Nucleation Mechanism of Microcrystalline Silicon Studied by Real Time Spectroscopic Ellipsometry and Infrared Spectroscopy

2000 ◽  
Vol 609 ◽  
Author(s):  
Hiroyuki Fujiwara ◽  
Yasutake Toyoshima ◽  
Michio Kondo ◽  
Akihisa Matsuda
Keyword(s):  
Plasma Treatment ◽  
Real Time ◽  
Spectroscopic Ellipsometry ◽  
Nucleation Mechanism ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Reflection Spectroscopy ◽  
Microcrystalline Silicon ◽  
Strained Si ◽  
Initial Layers

ABSTRACTWe have characterized a-Si:H initial layers for μc-Si:H nucleation by real time spectroscopic ellipsometry (SE) and infrared attenuated total reflection spectroscopy (ATR) to investigate the μc-Si:H formation mechanism. By performing Ar plasma treatment of a-Si:H layers, we confirmed a presence of a 2 monolayer thick sub-surface in a-Si:H layers. In the a-Si:H sub-surface that leads to the μc-Si:H nucleation, an important peak at ∼1937 cm−1 assigned to the SiHn complex was found in the ATR spectra. From H2 plasma treatment experiments, we proposed that this SiHn complex is formed by H insertion into strained Si-Si bonds. The SiHn complex formed in the a-Si:H sub-surface showed a clear relationship with the μc-Si:H nucleation. From these results, we conclude that the μc-Si:H nucleation occurs by the formation of the chemically active and flexible SiHn complexes in the 2 monolayer thick a-Si:H sub-surface.

scholarly journals Complex Investigation of High Efficiency and Reliable Heterojunction Solar Cell Based on an Improved Cu2O Absorber Layer

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4667
Author(s):  
Laurentiu Fara ◽  
Irinela Chilibon ◽  
Ørnulf Nordseth ◽  
Dan Craciunescu ◽  
Dan Savastru ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Reliability Analysis ◽  
High Performance ◽  
High Efficiency ◽  
Absorber Layer ◽  
Heterojunction Solar Cell ◽  
Complex Investigation ◽  
Heterojunction Solar Cells ◽  
Conduction Band Offset

This study is aimed at increasing the performance and reliability of silicon-based heterojunction solar cells with advanced methods. This is achieved by a numerical electro-optical modeling and reliability analysis for such solar cells correlated with experimental analysis of the Cu2O absorber layer. It yields the optimization of a silicon tandem heterojunction solar cell based on a ZnO/Cu2O subcell and a c-Si bottom subcell using electro-optical numerical modeling. The buffer layer affinity and mobility together with a low conduction band offset for the heterojunction are discussed, as well as spectral properties of the device model. Experimental research of N-doped Cu2O thin films was dedicated to two main activities: (1) fabrication of specific samples by DC magnetron sputtering and (2) detailed characterization of the analyzed samples. This last investigation was based on advanced techniques: morphological (scanning electron microscopy—SEM and atomic force microscopy—AFM), structural (X-ray diffraction—XRD), and optical (spectroscopic ellipsometry—SE and Fourier-transform infrared spectroscopy—FTIR). This approach qualified the heterojunction solar cell based on cuprous oxide with nitrogen as an attractive candidate for high-performance solar devices. A reliability analysis based on Weibull statistical distribution establishes the degradation degree and failure rate of the studied solar cells under stress and under standard conditions.

Enhancement of photovoltaic properties of CH3NH3PbBr3 heterojunction solar cells by modifying mesoporous TiO2 surfaces with carboxyl groups

2015 ◽  
Vol 3 (17) ◽  
pp. 9264-9270 ◽  
Author(s):  
Hyun Bin Kim ◽  
Iseul Im ◽  
Yeomin Yoon ◽  
Sang Do Sung ◽  
Eunji Kim ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Mesoporous Tio2 ◽  
Heterojunction Solar Cell ◽  
Carboxyl Groups ◽  
Photovoltaic Properties ◽  
Heterojunction Solar Cells ◽  
Light Absorber

In a novel heterojunction solar cell employing CH3NH3PbBr3 (MAPbBr3) as the light absorber, the introduction of a carboxylate monolayer on the mesoporous TiO2 surfaces significantly enhances JSC as well as VOC.

Sign in / Sign up

Export Citation Format

Share Document