Formation of MoO<sub>x</sub> barrier layer under atmospheric based condition to control MoSe<sub>2</sub> formation in CIGS thin film solar cell

Ong, Kam Hoe; Ramasamy, Agileswari K.; Arnou, Panagiota; Maniscalco, B.; Bowers, Jake W.; Kumar, Chakrabarty Chandan; Marsadek, Marayati

doi:10.1080/10667857.2018.1502512

Cited by 4 publications

(5 citation statements)

References 21 publications

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“…The standard back contact is Mo, which sometimes selenizes to form a thin interfacial MoSe 2 layer. Wide band gap p-type oxides such as MoO x have been also researched at the back interface, 458 but no work on wide gap chalcogenides for this layer could be found.…”

Section: Cigs Solar Cellsmentioning

confidence: 99%

Wide Band Gap Chalcogenide Semiconductors

et al. 2020

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Wide band gap semiconductors are essential for today's electronic devices and energy applications due to their high optical transparency, as well as controllable carrier concentration and electrical conductivity. There are many categories of materials that can be defined as wide band gap semiconductors. The most intensively investigated are transparent conductive oxides (TCOs) such as tin-doped indium oxide (ITO) and amorphous In-Ga-Zn-O (IGZO) used in displays, carbides (e.g. SiC) and nitrides (e.g. GaN) used in power electronics, as well as emerging halides (e.g. g-CuI) and 2D electronic materials (e.g. graphene) used in various optoelectronic devices. Compared to these prominent materials families, chalcogen-based (Ch = S, Se, Te) wide band gap semiconductors are less heavily investigated but stand out due to their propensity for ptype doping, high mobilities, high valence band positions (i.e. low ionization potentials), and broad applications in electronic devices such as CdTe solar cells. This manuscript provides a review of wide band gap chalcogenide semiconductors. First, we outline general materials design parameters of high performing transparent conductors, as well as the theoretical and experimental underpinnings of the corresponding research methods. We proceed to summarize progress in wide band gap (E G > 2 eV) chalcogenide materials, such as II-VI MCh binaries, CuMCh 2 chalcopyrites, Cu 3 MCh 4 sulvanites, mixed anion layered CuMCh(O,F), and 2D materials, among others, and discuss computational predictions of potential new candidates in this family, highlighting their optical and electrical properties. We finally review applications of chalcogenide wide band gap semiconductors, e.g. photovoltaic and photoelectrochemical solar cells, transparent transistors, and light emitting diodes, that employ wide band gap chalcogenides as either an active or passive layer. By examining, categorizing, and discussing prospective directions in wide band gap chalcogenides, this review aims to inspire continued research on this emerging class of transparent conductors and to enable future innovations for optoelectronic devices.

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Section: Cigs Solar Cellsmentioning

confidence: 99%

Wide Band Gap Chalcogenide Semiconductors

et al. 2020

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“…Moreover, transition metal oxide can be used to improve both rear passivation and hole-selective contact properties in thin-film solar cells based on Cu(In,Ga)Se2 (CIGS) [33]; furthermore, thin layer of MoOx, obtained by oxidation of Mo back contact, has also been applied to control the Se diffusion and the growth of MoSe2 in CIGS solar cells improving the rear passivation and the electrical properties of these devices [34]. Molybdenum oxide is also commonly used in perovskite solar cells to prevent sputtering damage to underlying layers [35] and as selective contact to extract photogenerated holes [35][36][37].…”

Section: Introductionmentioning

confidence: 99%

Sub-gap defect density characterization of molybdenum oxide: An annealing study for solar cell applications

et al. 2020

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The application of molybdenum oxide in the photovoltaic field is gaining traction as this material can be deployed in doping-free heterojunction solar cells in the role of hole selective contact. For modeling-based optimization of such contact, knowledge of the molybdenum oxide defect density of states (DOS) is crucial. In this paper, we report a method to extract the defect density through nondestructive optical measures, including the contribution given by small polaron optical transitions. The presence of defects related to oxygen-vacancy and of polaron is supported by the results of our opto-electrical characterizations along with the evaluation of previous observations. As part of the study, molybdenum oxide samples have been evaluated after post-deposition thermal treatments. Quantitative results are in agreement with the result of density functional theory showing the presence of a defect band fixed at 1.1 eV below the conduction band edge of the oxide. Moreover, the distribution of defects is affected by post-deposition treatment.

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“…This indicates that the molybdenum oxide inhibited selenium accumulation on the molybdenum surface to form molybdenum selenide to a certain extent. Thermodynamic calculations [ 21,29,32 ] were conducted to prove that oxygen has better oxidative activity to molybdenum than selenium, so it can react with molybdenum more easily to generate molybdenum oxide. Thus, the molybdenum oxide effectively inhibited the reaction between the molybdenum and selenium at the Mo/CIGS interface.…”

Section: Resultsmentioning

confidence: 99%

Significant Passivation Effect of Cu(In, Ga)Se₂ Solar Cells via Back Contact Surface Modification Using Oxygen Plasma

et al. 2021

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Molybdenum back contact plays a significant role in chalcopyrite Cu(In, Ga)Se2 (CIGS) solar cells. A molybdenum oxide intermediate layer is applied to optimize the back contact from the aspect of absorber crystal growth regulation and back surface field reconstruction. A novel molybdenum oxide preparation method is introduced through oxygen plasma treatment of the molybdenum layer. CIGS film is obtained by sputtering from a quaternary target with post‐selenization. The shortage of Cu and Se in the middle of the absorption layer causes crystallization stratification. A bidirectional regulation method for controlling intermediate fine grains is proposed. Superior crystallinity is produced to facilitate carriers’ transport and reduce recombination at grain boundaries. Back passivation is achieved by forming a reverse p–n junction on the back surface. Despite the formation of this reverse junction, the efficiency of the device is still improved because the transport of holes is assisted by the molybdenum oxide's gap states. Thus, back surface recombination is effectively reduced by back passivation, leading to the increase in open‐circuit voltage (Voc) and fill factor (FF). The power conversion efficiency of treated solar cells increases by 34.1%. An innovative direction is proposed to optimize the back contact of CIGS solar cells in this study.

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Formation of MoO_x barrier layer under atmospheric based condition to control MoSe₂ formation in CIGS thin film solar cell

Cited by 4 publications

References 21 publications

Wide Band Gap Chalcogenide Semiconductors

Wide Band Gap Chalcogenide Semiconductors

Sub-gap defect density characterization of molybdenum oxide: An annealing study for solar cell applications

Significant Passivation Effect of Cu(In, Ga)Se₂ Solar Cells via Back Contact Surface Modification Using Oxygen Plasma

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Formation of MoOx barrier layer under atmospheric based condition to control MoSe2 formation in CIGS thin film solar cell

Cited by 4 publications

References 21 publications

Wide Band Gap Chalcogenide Semiconductors

Wide Band Gap Chalcogenide Semiconductors

Sub-gap defect density characterization of molybdenum oxide: An annealing study for solar cell applications

Significant Passivation Effect of Cu(In, Ga)Se2 Solar Cells via Back Contact Surface Modification Using Oxygen Plasma

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Formation of MoO_x barrier layer under atmospheric based condition to control MoSe₂ formation in CIGS thin film solar cell

Significant Passivation Effect of Cu(In, Ga)Se₂ Solar Cells via Back Contact Surface Modification Using Oxygen Plasma