Spectroscopic review of hydrogenated, carbonated and oxygenated group IV alloys

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

doi:10.1016/j.vibspec.2022.103387

Cited by 8 publications

(7 citation statements)

References 100 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The peak at 500 cm À1 is associated to a poly-crystalline phase [20,21], with the Raman shift in reference to mono-c-Si resulting from strain from the crystalline grains. Similar Raman shifts are observed in nano-c-Si and micro-c-Si, where crystalline grains are embedded in an amorphous Si phase [22]. In these materials the exact shift was demonstrated to be a function of the crystalline grain size [20].…”

Section: Methodssupporting

confidence: 69%

The optical performance of random and periodic textured mono crystalline silicon surfaces for photovoltaic applications

et al. 2022

View full text Add to dashboard Cite

Surface textures that result in high optical yields are crucial for high efficiency photovoltaic (PV) devices. In this work three different texturing approaches are presented that result in smooth concave structures devoid of sharp features. Such features can sustain the crack-free growth of device quality nano- to poly-crystalline materials such as nano-crystalline silicon, perovskites or C(I)GS, facilitating routes towards hybrid multijunction PV devices. A sacrificial implanted poly-c-Si layer is used to develop a random surface texture for the first texturing approach (Tsac). The influence of the processing conditions, such as layer thickness, implantation energy, dose and ion type, annealing time and temperature, of the sacrificial layer on the developed surface features is investigated. Additionally, a photolithographically developed honeycomb texture (Thoney) is presented. The influence of mask design on the honeycomb features is discussed and a relation is established between the honeycomb period and crack formation in nano-crystalline silicon layers. The reflective properties (spectral reflection, haze in reflection and angular intensity distribution) of these approaches are characterized and compared to a third texturing approach, Tsp, the result of chemically smoothened pyramidal <111> features. It was demonstrated that high optical scattering yields can be achieved for both Thoney and Tsp. Additionally, the performance of a-Si/nc-Si tandem devices processed onto the different textures is compared using both optical device simulations and real device measurements. Simulations demonstrate strong improvements in Jsc-sum (≈45%), in reference to a flat surface, and high Voc*FF of over 1 V are demonstrated for Tsp.

show abstract

Section: Methodssupporting

confidence: 69%

The optical performance of random and periodic textured mono crystalline silicon surfaces for photovoltaic applications

et al. 2022

View full text Add to dashboard Cite

show abstract

“…The dashed vertical lines show the wave number position of Raman bands for amorphous germanium and amorphous silicon as found in literature [61][62][63]. Ge-Si local bonds produces Raman lines between the pure substances [61][62][63]. In the Ge0.8Si0.2 film (Figure 4b), there are no Si-Si bonds.…”

Section: Sample Characterizationmentioning

confidence: 66%

“…The amorphous Ge0.25Si0.75 film was obtained by using three instead of one quadrants of Si pieces for the sputter-target (see Figure 2a,b). The dashed vertical lines show the wave number position of Raman bands for amorphous germanium and amorphous silicon as found in literature [61][62][63]. Ge-Si local bonds produces Raman lines between the pure substances [61][62][63].…”

Section: Sample Characterizationmentioning

confidence: 82%

In-situ Neutron Reflectometry to Determine Ge Self-Diffusivities and Activation Energy of Diffusion in Amorphous Ge_0.8Si_0.2

Hüger,

Stahn,

Schmidt

2023

EPJ Web Conf.

View full text Add to dashboard Cite

Amorphous Ge-Si solid solutions are an interesting class of materials from the fundamental as well as the technological point of view. Self-diffusion of the constituents is an important process because of the inherent metastability. While self-diffusion was already examined in crystalline GexSi1-x (0 < x <1) this is not the case for the amorphous counterparts. This work reports on Ge self-diffusivities obtained from insitu neutron reflectometry measurements during isothermal annealing of ion-beam sputter-deposited amorphous Ge0.8Si0.2 films. The diffusivities are modified peculiarly fast with annealing time by a maximum factor of two due to structural relaxation. The diffusivities in the relaxed state are lower (higher) than in amorphous germanium (silicon). They follow the Arrhenius law and show an activation energy of (2.06 ± 0.1) eV, which equals that of amorphous germanium, but differs from that of amorphous silicon. Thus, it is concluded that the diffusion mechanism of Ge in amorphous Ge0.8Si0.2 and Ge are similar, despite of the presence of dispersed 20 at.% of Si.

show abstract

“…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%

“…[ 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. We demonstrated that the rate of oxidation is directly related to the density of the material and specifically the fraction of nano‐sized voids in the material.…”

Section: The Challenges Of Processing Ge:hmentioning

confidence: 99%

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

et al. 2022

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Spectroscopic review of hydrogenated, carbonated and oxygenated group IV alloys

Cited by 8 publications

References 100 publications

The optical performance of random and periodic textured mono crystalline silicon surfaces for photovoltaic applications

The optical performance of random and periodic textured mono crystalline silicon surfaces for photovoltaic applications

In-situ Neutron Reflectometry to Determine Ge Self-Diffusivities and Activation Energy of Diffusion in Amorphous Ge_0.8Si_0.2

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

Contact Info

Product

Resources

About

Spectroscopic review of hydrogenated, carbonated and oxygenated group IV alloys

Cited by 8 publications

References 100 publications

The optical performance of random and periodic textured mono crystalline silicon surfaces for photovoltaic applications

The optical performance of random and periodic textured mono crystalline silicon surfaces for photovoltaic applications

In-situ Neutron Reflectometry to Determine Ge Self-Diffusivities and Activation Energy of Diffusion in Amorphous Ge0.8Si0.2

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

Contact Info

Product

Resources

About

In-situ Neutron Reflectometry to Determine Ge Self-Diffusivities and Activation Energy of Diffusion in Amorphous Ge_0.8Si_0.2