Study of the spectral response for HgCdTe long-wavelength detectors with applied stress

ABSTRACTDilution by Ar of silane plasma has been reported to increase the stability of a-Si:H films. A critical question is whether Ar diluted i-layers offer higher stabilized solar cell efficiencies than the conventional hydrogen dilution method. We have fabricated a-Si:H p-i-n solar cells with RF-PECVD i-layers by Ar dilution of silane. Ar dilution ratio (ADR, Ar/SiH4), RF power,pressure, and i-layer thickness were varied. At low ADR < 20, such solar cells show comparable initial efficiencies and stability as those devices having H2-diluted i-layers of similar thickness. For cells made with ADR > 20, the initial efficiency decreases dramatically with further increase in Ar dilution, and light soaking causes only mild changes in efficiencies. The stabilized efficiencies of cells made with high ADR are inferior to the cells produced with low ADR or cells prepared by H2 dilution. Further, Voc of solar cells made with high ADR (> 50) decreases substantially in ambient, indicating a porous microstructure susceptible to oxidation. While thermal annealing improves the Voc, a full recovery of Voc is made by accelerated light soaking.The combination of high power and high ADR can lead to nanocrystalline silicon (nc-Si:H) growth, although nucleation is much more difficult to attain by the Ar dilution method compared to hydrogen dilution. We have succeeded in fabricating p-i-n solar cells with nc-Si:H i-layers prepared by the Ar dilution approach. The double dilution by Ar and hydrogen of silane (Ar+H2+SiH4) can result in nc-Si:H i-layers with enhanced long wavelength spectral response compared to devices incorporating nc-Si:H i-layers grown by H2 dilution only. The nc-Si:H solar cells with Ar+H2 diluted i-layers exhibit no light-induced degradation.Using energetic Ar-rich plasma, in a process much simpler than the traditional nc-Si:H technique, doped a-Si:H thin layers can be prepared to form excellent tunnel junctions for multi-junction solar cells. We demonstrate such a novel, non-contaminating tunnel junction in tandem a-Si/a-Si and a-Si/nc-Si solar cells entirely fabricated in a single-chamber RF-PECVD system.

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Thin-film Photodiode with an a-Si:H/nc-Si:H Absorption Bilayer

MRS Proceedings ◽

10.1557/opl.2011.952 ◽

2011 ◽

Vol 1321 ◽

Author(s):

Y. Vygranenko ◽

M. Vieira ◽

A. Sazonov

Keyword(s):

Thin Film ◽

Leakage Current ◽

Near Infrared ◽

Spectral Response ◽

Nanocrystalline Silicon ◽

Depletion Region ◽

Long Wavelength ◽

Near Ultraviolet ◽

High Bias ◽

Bias Range

ABSTRACTWe report on the fabrication and characterization of n+-n-i-δi-p thin-film photodiodes with an active region comprising a hydrogenated nanocrystalline silicon (nc-Si:H) n-layer and a hydrogenated amorphous silicon (a-Si:H) i-layer. The combination of wide- and narrow-gap absorption layers enables the spectral response extending from the near-ultraviolet (NUV) to the near-infrared (NIR) region. Moreover, in the low-bias range, when only the i-layer is depleted, the leakage current is significantly lower than that in the conventional nc-Si:H n+-n-p+ photodiode deposited under the same deposition conditions. Device with the 900nm/400nm thick n-i-layers exhibits a reverse dark current density of 3 nA/cm2 at −1V. In the high-bias range, when the depletion region expands within the n-layer, the magnitude of the leakage current depends on electronic properties of nc-Si:H. The density of shallow and deep states, and diffusion length of holes in the n-layer have been estimated from the capacitance-voltage characteristics and from the bias dependence of the long-wavelength response, respectively. To improve the quantum efficiency in the NIR-region, we have also implemented a Cr / ZnO:Al back reflector. The observed long-wavelength spectral response is about twice as high as that for a reference photodiode without ZnO:Al layer. Results demonstrate the feasibility of the photodiode for low-level light detection in the NUV-to-NIR spectral range.

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Modeling of HgCdTe Heterojunction Devices

MRS Proceedings ◽

10.1557/proc-90-39 ◽

1986 ◽

Vol 90 ◽

Cited By ~ 3

Author(s):

Ken Zanio ◽

Ken Hay

Keyword(s):

Conduction Band ◽

Infrared Detectors ◽

Minority Carrier ◽

Spectral Response ◽

Long Wavelength ◽

Barrier Formation ◽

Diffusion Parameters ◽

Doping Profiles ◽

Heterostructure Devices ◽

And Diffusion

ABSTRACTA model for generating the composition and doping profiles from growth and diffusion parameters was developed for heterostructure devices. Poisson's equation was applied to these structures to predict barriers in the conduction band to minority carrier flow for long wavelength HgCdTe infrared detectors prepared by LPE techniques. Spectral response and quantum efficiency measurements illustrate the presence of these barriers and support the use of this model in predicting barrier formation.

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Optimization ofμc-Si1−xGex:H Single-Junction Solar Cells with Enhanced Spectral Response and Improved Film Quality

International Journal of Photoenergy ◽

10.1155/2015/382814 ◽

2015 ◽

Vol 2015 ◽

pp. 1-9

Author(s):

Yen-Tang Huang ◽

Pei-Ling Chen ◽

Po-Wei Chen ◽

Hung-Jung Hsu ◽

Cheng-Hang Hsu ◽

...

Keyword(s):

Solar Cells ◽

Spectral Response ◽

Rf Power ◽

Single Junction ◽

Long Wavelength ◽

Tandem Cell ◽

Cell Efficiency ◽

Photo Conductivity ◽

Gas Ratio ◽

Incorporation Efficiency

Effects of RF power on optical, electrical, and structural properties ofμc-Si1−xGex:H films was reported. Raman and FTIR spectra fromμc-Si1−xGex:H films reflected the variation in microstructure and bonding configuration. Unlike increasing the germane concentration for Ge incorporation, low RF power enhanced Ge incorporation efficiency inμc-Si1−xGex:H alloy. By decreasing RF power from 100 to 50 W at a fixed reactant gas ratio, the optical bandgap ofμc-Si1−xGex:H was reduced owing to the increase in Ge content from 11.2 to 23.8 at.%, while Ge-related defects and amorphous phase were increased. Consequently, photo conductivity of 1.62 × 10−5 S/cm was obtained for theμc-Si1−xGex:H film deposited at 60 W. By applying 0.9 μm thickμc-Si1−xGex:H absorber withXCof 48% and [Ge] of 16.4 at.% in the single-junction cell, efficiency of 6.18% was obtained. The long-wavelength response ofμc-Si1−xGex:H cell was significantly enhanced compared with theμc-Si:H cell. In the case of tandem cells, 0.24 μm a-Si:H/0.9 μmμc-Si1−xGex:H tandem cell exhibited a comparable spectral response as 0.24 μm a-Si:H/1.4 μmμc-Si:H tandem cell and achieved an efficiency of 9.44%.

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A facile way to improve the efficiency of perovskite/silicon four-terminal tandem solar cell based on the optimization of long-wavelength spectral response

10.1063/1.5123886 ◽

2019 ◽

Author(s):

Shude Zhang ◽

Xiang Fang ◽

Hongwei Hu ◽

Jiansheng Jie ◽

Xiaohong Zhang ◽

...

Keyword(s):

Solar Cell ◽

Spectral Response ◽

Tandem Solar Cell ◽

Long Wavelength

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Spectral response and device performance tuning of long-wavelength InAs QDIPs

Infrared Physics & Technology ◽

10.1016/j.infrared.2010.12.020 ◽

2011 ◽

Vol 54 (3) ◽

pp. 233-236 ◽

Cited By ~ 4

Author(s):

H.S. Ling ◽

S.Y. Wang ◽

C.P. Lee

Keyword(s):

Spectral Response ◽

Performance Tuning ◽

Device Performance ◽

Long Wavelength

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Investigation of Textured Back Reflectors for Microcrystalline Silicon Based Solar Cells

MRS Proceedings ◽

10.1557/proc-557-731 ◽

1999 ◽

Vol 557 ◽

Cited By ~ 16

Author(s):

O. Kluth ◽

O. Vetterl ◽

R. Carius ◽

F. Finger ◽

S. Wieder ◽

...

Keyword(s):

Solar Cells ◽

Near Infrared ◽

Spectral Response ◽

Short Circuit ◽

Chemical Vapour ◽

Root Mean Square Roughness ◽

Microcrystalline Silicon ◽

Feature Size ◽

Long Wavelength ◽

Back Reflectors

AbstractMicrocrystalline silicon (μc-Si:H) solar cells require an effective light trapping in the near infrared (NIR) to enhance the long wavelength spectral response. For this purpose we investigated back reflectors based on texture-etched ZnO/Ag stacks prepared on glass substrates by magnetron sputtering. With decreasing sputter pressure the resulting surface texture of the glass/Ag/ZnO substrates after etching exhibits a larger feature size and root mean square roughness. The increase in feature size corresponds to an increase of diffuse reflectivity. Applied in microcrystalline solar cells prepared by VHF plasma enhanced chemical vapour deposition (PECVD), the reflectors showing the largest feature size (prepared at the lowest possible sputter pressure) yielded the highest long wavelength spectral response. The μc-Si n-i-p cells prepared on the latter back reflector exhibited efficiencies of 6.9 % (short circuit current density jsc= 18.8 mA/cm2) and 7.5 % (jsc=25 mA/cm2) for an i-layer thickness of 1 μm and 3.5 μm, respectively.

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Preparation of Narrow-gap a-Si:H Solar Cells by VHF-PECVD Technique

MRS Proceedings ◽

10.1557/proc-1245-a07-07 ◽

2010 ◽

Vol 1245 ◽

Author(s):

Do Yun Kim ◽

Ihsanul Afdi Yunaz ◽

Shunsuke Kasashima ◽

Shinsuke Miyajima ◽

Makoto Konagai

Keyword(s):

Thin Films ◽

Solar Cells ◽

Solar Cell ◽

Spectral Response ◽

Short Circuit ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Open Circuit ◽

Hydrogen Flow ◽

Long Wavelength

AbstractOptical, electrical and structural properties of silicon films depending on hydrogen flow rate (RH), substrate temperature (TS), and deposition pressure (PD) were investigated. By decreasing RH and increasing TS and PD, the optical band gap (Eopt) of silicon thin films drastically declined from 1.8 to 1.63 eV without a big deterioration in electrical properties. We employed all the investigated Si thin films for p-i-n structured solar cells as absorbers with i-layer thickness of 300 nm. From the measurement of solar cell performances, it was clearly observed that spectral response in long wavelength was enhanced as Eopt of absorber layers decreased. Using the solar cell whose Eopt of i-layer was 1.65 eV, the highest QE at long wavelength with the short circuit current density (Jsc) of 16.34 mA/cm2 was achieved, and open circuit voltage (Voc), fill factor (FF), and conversion efficiency (η) were 0.66 V, 0.57, and 6.13%, respectively.

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