One-stage pulsed laser deposition of conductive zinc oxysulfide layers

Bereznev, Sergei; Kocharyan, Hrachya; Maticiuc, Natalia; Naidu, Revathi; Volobujeva, Olga; Tverjanovich, A. S.; Kois, J.

doi:10.1016/j.apsusc.2017.07.078

Cited by 10 publications

(12 citation statements)

References 23 publications

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“…The observed effect can be attributed to the evaporation of Se during the deposition process before the nucleation stage, similarly to that reported for sulfur-based ternary Zn(O,S) films grown by PLD. 22 The surface morphology and cross-sectional views of films deposited at substrate temperatures varying from RT to 650 °C are compared in Figure 1. It should be noted that the morphological properties of films fabricated in the temperature region from RT to 400 °C were very similar (see Figure 1, Figure S2 in the SI).…”

Section: Resultsmentioning

confidence: 99%

“…This phenomenon is similar to that reported for the PLDgrown Zn(O,S) layers in our previous work. 22 For instance, the thicknesses of Zn(O,S) films grown at RT and 400 °C have The atomic percentages for elements and film thickness were determined by averaging the values obtained from three measurements for each sample. been approximately 650 and 580 nm, respectively.…”

Section: Resultsmentioning

confidence: 99%

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Pulsed Laser Deposition of Zn(O,Se) Layers for Optoelectronic Application

Polivtseva

Spalatu

Abdalla

et al. 2018

ACS Appl. Energy Mater.

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Zinc oxyselenideZn(O,Se)could become a novel buffer layer in solar cells and a functional layer in different optoelectronic devices. In this study, we systematically investigated the influence of the deposition temperature ranging from room temperature (RT) to 650 °C on the structural and optoelectronic properties of Zn(O,Se) layers grown on photovoltaic (PV) glass substrates by one-step pulsed laser deposition in a high vacuum. All layers were characterized using energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), X-ray diffractometry (XRD), UV−vis spectroscopy, and the Hall and van der Pauw technique. We demonstrated that polycrystalline, uniform, and electrically conductive Zn(O,Se) layers were grown at the substrate temperatures of 500−650 °C, while those layers grown at temperatures below 500 °C were characterized as amorphous and exhibiting a semi-insulating behavior. According to the XRD data, single-phase layers consisting of a ternary Zn(O,Se) phase were formed only at 500 °C. The lattice parameters monotonously decreased with both increasing deposition temperature and lowering Se concentrations in the films. The electron density increased significantly from 1.0 × 10 14 to 3.2 × 10 18 when changing the substrate temperature from 500 to 550 °C. We attributed these changes to the formation of vacancy-type defects in the Zn(O,Se) system. For the first time, we demonstrated the applicability of Zn(O,Se) as a buffer layer in a complete solar cell structure. We developed a prospective superstrate configuration FTO/Zn(O,Se)/CdTe/Te/Ni solar cell exhibiting a cell efficiency of 7.6% (FTO, fluorine-doped tin oxide). Our findings revealed the great potential of Zn(O,Se) to replace conventional CdS buffer layers and to open up new strategies to improve solar cell performance.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Pulsed Laser Deposition of Zn(O,Se) Layers for Optoelectronic Application

Polivtseva

Spalatu

Abdalla

et al. 2018

ACS Appl. Energy Mater.

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“…With increasing substrate temperature, the absorption edges shifted to a lower wavelength (blue shift). The optical band gaps of all Zn(O,Se) films were evaluated based on the Tauc relation (2) 7,54 by plotting hv versus (αhv) 2 and extrapolating the linear part of the plot to hv axis (x axis) (see Supplementary Fig. S8).…”

Section: Resultsmentioning

confidence: 99%

“…Film thickness and morphology were characterized by means of high-resolution scanning electron microscope (HR-SEM) Zeiss Merlin equipped with In-Lens SE detector for topographic imaging. Elemental analysis was conducted using Energy Dispersive X-ray (EDX) system (Bruker EDX-XFlash6/30 detector) 7 . XPS measurements were performed with a Kratos Axis Ultra DLD XPS spectrometer with monochromatic Al K α radiation (1486.6 eV).…”

Section: Methodsmentioning

confidence: 99%

Pulsed laser deposition of Zn(O,Se) layers in nitrogen background Pressure

Abdalla

Bereznev

Spalatu

et al. 2019

Sci Rep

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Zinc oxy-selenide Zn(O,Se) is a novel material, that can replace the toxic CdS buffer layer in thin film solar cells and other optoelectronic devices. In this paper a systematic study of the structural, optical and electrical properties of Zn(O,Se) layers, grown by pulsed laser deposition under 50 mTorr of nitrogen background pressure, over a wide range of the substrate temperature, from RT to 600 °C, is reported. XRD, Raman, HR-SEM, XPS, UV-Vis techniques and Hall effect measurements have been used to investigate the structural, and optoelectronic properties of Zn(O,Se) layers. XRD analysis revealed that the polycrystalline ternary Zn(O,Se) phase formed at 500 °C. Raman analysis confirmed the formation of the polycrystalline Zn(O,Se) phase at 500 °C and an amorphous phase at substrate temperatures below 500 °C. Similarly, XPS analysis accompanied with the modified Auger parameters confirmed formation of ternary Zn(O,Se) layer at 500 °C as well. HR-SEM investigation showed the growth of homogenous, dense and adherent films onto a glass substrate. Furthermore, optical studies revealed that all prepared films are practically transparent in the visible region of the spectrum, with a band gap around 3 eV. Hall effect measurements revealed that conductivity, and electron concentration, increased by four orders of magnitude at 600 °C. It was found, that nitrogen background pressure maintained stable ratios of elemental contents in the whole range of the substrate temperature for Zn(O,Se) layers.

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“…Thus far, attempts of S‐doping into crystalline ZnO or O‐doping into crystalline ZnS have been made to modify the physical properties of host crystals . Alloy films of ZnO and ZnS have also been used as a buffer layer for solar cells of CuIn 1− x Ga x Se 2− y S y ,19–25 Cu 2 ZnSnS 4 ,26 and SnS because of their controllable band alignment. While these studies reported that ZnO x S y could become amorphous for an intermediate composition range, the electrical transport properties of amorphous ZnO x S y (a‐ZnO x S y ) thin films, including carrier concentration and Hall mobility, have not been studied, except for the resistivity of a film (> 10 2 Ωcm for x = 0.71) .…”

Section: Transport Properties and Chemical Composition Of A Conductivmentioning

confidence: 99%

High‐Mobility and Air‐Stable Amorphous Semiconductor Composed of Earth‐Abundant Elements: Amorphous Zinc Oxysulfide

Zhu

Yamazaki

Жен

et al. 2019

Adv Elect Materials

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Amorphous oxide semiconductors (AOSs) have been studied extensively as the channel layer of thin-film transistors and as the transparent conducting electrode of optoelectronic devices due to their high electron mobility (>10 cm 2 V −1 s −1) and low processing temperature, which makes them applicable to flexible electronics on plastic substrates. [1-4] In general, AOSs are alloys of post-transition metal oxides with different crystal structures and cation radii, such as In 2 O 3-Ga 2 O 3-ZnO (IGZO). However, most high-mobility AOSs contain the rare metal In as their main component, and thus continuous efforts have been made to develop In-free alternatives. [5-9] Recently, it was reported that amorphous ZnO x N y , an alloy of ZnO (wurtzite structure) and Zn 3 N 2 (anti-bixbyite structure), exhibits very high mobility (>100 cm 2 V −1 s −1) and good performance as the channel layer of thin-film transistors (TFTs). [10-13] These studies point to Zn-based mixed-anion compounds as promising candidates for rare-metal-free amorphous semiconductors. However, ZnO x N y is chemically unstable in air, presumably owing to the weak chemical bonds between Zn and N. It has been reported that an amorphous ZnO x N y thin film gradually lost its N and was fully oxidized after 30 days under ambient conditions. [14] Thus, a new combination of chemically stable Zn-based compounds is needed. In this study, we focused on ZnO x S y , an alloy of ZnO and ZnS with a zinc-blende structure, as a candidate for such compounds, because ZnS is stable in air. Thus far, attempts of S-doping into crystalline ZnO or O-doping into crystalline ZnS have been made to modify the physical properties of host crystals. [15-18] Alloy films of ZnO and ZnS have also been used as a buffer layer for solar cells of CuIn 1−x Ga x Se 2−y S y , [19-25] Cu 2 ZnSnS 4 , [26] and SnS [27-29] because of their controllable band alignment. While these studies reported that ZnO x S y could become amorphous for an intermediate composition range, [18,20,30-32] the electrical transport properties of amorphous ZnO x S y (a-ZnO x S y) thin films, including carrier concentration and Hall mobility, have not been studied, except for the Amorphous oxide semiconductors have been widely studied as key materials for flat panel displays and flexible electronics devices. Recently, it has been reported that an amorphous mixed-anion semiconductor consisting of only earth-abundant elements, zinc oxynitride, shows high electron mobility and good performance as the channel layer of a thin-film transistor. However, amorphous zinc oxynitrides are unstable in air. It is demonstrated that another type of earth-abundant amorphous mixed-anion semiconductor, amorphous zinc oxysulfide (a-ZnO x S y) thin film, exhibits electron mobilities comparable to those of conventional amorphous oxide semiconductors, in addition to good chemical stability under ambient conditions. a-ZnO x S y thin films with a wide compositional range are fabricated through pulsed laser deposition, by alternately depositing ZnO a...

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One-stage pulsed laser deposition of conductive zinc oxysulfide layers

Cited by 10 publications

References 23 publications

Pulsed Laser Deposition of Zn(O,Se) Layers for Optoelectronic Application

Pulsed Laser Deposition of Zn(O,Se) Layers for Optoelectronic Application

Pulsed laser deposition of Zn(O,Se) layers in nitrogen background Pressure

High‐Mobility and Air‐Stable Amorphous Semiconductor Composed of Earth‐Abundant Elements: Amorphous Zinc Oxysulfide

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