The impact of processing conditions and post-deposition oxidation on the opto-electrical properties of hydrogenated amorphous and nano-crystalline Germanium films

Vrijer, Thierry de; Ravichandran, Ashwath; Bouazzata, Bilal; Smets, Arno H. M.

doi:10.1016/j.jnoncrysol.2020.120507

Cited by 9 publications

(21 citation statements)

References 44 publications

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“…A dense Ge:H phase, unlike a porous Ge:H phase, has an average bond length small enough to prevent the in-diffusion of H 2 O but not the in-diffusion of O 2 . 12 Moreover, if a different species was involved in the oxidation reaction, a more distinct difference between Ge–O signatures could be expected. 2.…”

Section: The Oxidation and Etching Behaviour Of Ge:h By Watermentioning

confidence: 99%

Infrared analysis of catalytic CO₂ reduction in hydrogenated germanium

Vrijer

Smets

2022

Phys. Chem. Chem. Phys.

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Section: The Oxidation and Etching Behaviour Of Ge:h By Watermentioning

confidence: 99%

Infrared analysis of catalytic CO₂ reduction in hydrogenated germanium

Vrijer

Smets

2022

Phys. Chem. Chem. Phys.

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“…In this section, the high level relations between the structural and opto-electrical characteristics are addressed. For the films presented in Figure 2 more information about the relation between the processing conditions and structural characteristics, as well as more detailed structural investigation of the films, is provided for GeCSn, [20] Ge, [22,[24][25][26] SiGe, [22,27] SiO. [24] From these collective works, three structural characteristics through which a change in density can be realized.…”

Section: Why Different Group IV Alloysmentioning

confidence: 99%

“…This effect, a reaction in which oxygen introduced in the material postdeposition results in the passivation of defects, decreasing the defect density as well the E act , has been discussed in more detail in earlier work. [24] A relatively large defect density in the Ge:H films would also explain the poor photoresponse of the Ge:H films and improvement of 𝜎 ph /𝜎 d upon oxidation. The low photoresponse indicates that only a small fraction of photo-generated charge carriers are collected.…”

Section: The Right Processing Windowmentioning

confidence: 99%

“…The electrical properties, which proved most sensitive to degradation, of the films are presented in improves the electrical characteristics of the films, as discussed in. [22,24] Moreover, the a/nc-Ge:H films are fully etched in DI water in the 10-100 hrs period. The reactions involved in the Ge:H consumption and the relation between material density, etch rate and type of reaction are discussed in detail elsewhere.…”

Section: Gex Alloysmentioning

confidence: 99%

“…It was demonstrated in earlier work that for the majority of the processed samples, for a very large part of the processing window, a signature in the FTIR spectra appeared within minutes after deposition, that is related to the post‐deposition oxidation of the Ge:H films. [ 24 ] We argued that this post‐deposition reaction is related to the microscopic properties of the Ge:H films. In subsequent work, we found that post‐deposition not only an oxidation reaction occurred, but also a carbisation reaction, [ 22,26 ] which likely involves some form of catalytic CO 2 reduction.…”

Section: The Challenges Of Processing Ge:hmentioning

confidence: 99%

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Opto‐Electrical Properties of Group IV Alloys: The Inherent Challenges of Processing Hydrogenated Germanium

et al. 2022

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In this paper the opto-electrical nature of hydrogenated group IV alloys with optical bandgap energies ranging from 1.0 eV up to 2.3 eV are studied. The fundamental physical principles that determine the relation between the bandgap and the structural characteristics such as material density, elemental composition, void fraction and crystalline phase fraction are revealed. Next, the fundamental physical principles that determine the relation between the bandgap and electrical properties such as the dark conductivity, activation energy, and photoresponse are discussed. The unique wide range of IV valence alloys helps to understand the nature of amorphous (a-) and nanocrystalline (nc-) hydrogenated (:H) germanium films with respect to the intrinsicity, chemical stability, and photoresponse. These insights resulted in the discovery of i) a processing window that results in chemically stable Ge:H films with the lowest reported dark conductivity values down to 4.6•10 -4 (𝛀 •cm) -1 for chemical vapor deposited Ge:H films, and ii) O, C and Sn alloying approaches to improve the photoresponse and chemical stability of the a/nc-Ge:H alloys.

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Novel semi‐transparent solar cell based on ultrathin multiple Si/Ge quantum wells

Meddeb

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Flathmann

et al. 2022

Progress in Photovoltaics

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Unlike conventional opaque solar cells, semi-transparent solar cells enable simultaneous electricity generation and light transmission. Along with solar energy harvesting, the offered multiple functionalities of these technologies, such as aesthetic appearance, visual comfort and thermal management, open diverse integration opportunities into versatile technological applications. In this work, the first demonstration of a novel semi-transparent solar cell based on ultrathin hydrogenated amorphous Si/Ge multiple quantum wells (MQW) is reported. Through optoelectronic modelling, the advantages of ultrathin MQW as photoactive material to overcome the intrinsic limitations of thin (20 nm) and ultrathin (2.5 nm) single quantum well (SQW) counterparts are explained. This allows extra degree of freedom for both optical design and bandgap engineering. Mainly, the multiplication of the QWs number in a periodic configuration, taking advantage of effective synergy between electronic and photonic confinements, leads to an improvement of photocurrent, while preserving high voltage and fill factor and ensuring significant transparency. The MQW new concept yields a boost in power conversion efficiency up to 3.4% and a considerable average visible transmission of about 33%. A light utilization efficiency above 1.1% is achieved, which can be considered as one of the highest among inorganic semitransparent solar cell technologies. The successful demonstration of ultrathin semitransparent Si/Ge MQW solar cells indicates the promising integration potential of this emerging photovoltaic technology for supplying systems in relevant applications such as in buildings, vehicles and greenhouses.

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The impact of processing conditions and post-deposition oxidation on the opto-electrical properties of hydrogenated amorphous and nano-crystalline Germanium films

Cited by 9 publications

References 44 publications

Infrared analysis of catalytic CO₂ reduction in hydrogenated germanium

Infrared analysis of catalytic CO₂ reduction in hydrogenated germanium

Opto‐Electrical Properties of Group IV Alloys: The Inherent Challenges of Processing Hydrogenated Germanium

Novel semi‐transparent solar cell based on ultrathin multiple Si/Ge quantum wells

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The impact of processing conditions and post-deposition oxidation on the opto-electrical properties of hydrogenated amorphous and nano-crystalline Germanium films

Cited by 9 publications

References 44 publications

Infrared analysis of catalytic CO2 reduction in hydrogenated germanium

Infrared analysis of catalytic CO2 reduction in hydrogenated germanium

Opto‐Electrical Properties of Group IV Alloys: The Inherent Challenges of Processing Hydrogenated Germanium

Novel semi‐transparent solar cell based on ultrathin multiple Si/Ge quantum wells

Contact Info

Product

Resources

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Infrared analysis of catalytic CO₂ reduction in hydrogenated germanium

Infrared analysis of catalytic CO₂ reduction in hydrogenated germanium