Absolute <i>in situ</i> measurement of surface dangling bonds during a-Si:H growth

Aarts, Imp Igor; Pipino, Acr andrew; Sanden, van de Mcm Richard; Kessels, Wmm Erwin

doi:10.1063/1.2727561

Cited by 20 publications

(18 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This prediction is in agreement ͑i.e., of the order of magnitude of 10 −2 ͒ with ESR measurements, 13 but it is higher than the DB coverage measured by Aarts et al 14 These surface DBs promote surface hydride dissociation reactions from SiH 3͑s͒ to SiH 2͑s͒ through low-barrier DB-mediated pathways ͑E a = 0.16-0.33 eV͒, but their surface coverage is low dur- ing a-Si:H growth throughout the temperature range of interest. The role of DBs in promoting hydride dissociation and sequential dissociation reactions has also been inferred based on experiments.…”

Section: -6mentioning

confidence: 76%

“…This dangling-bond-based growth model has been used to explain the temperature independence of the surface reaction and sticking probabilities during a-Si:H film growth. Nevertheless, a growth model based on these surface reactions cannot describe satisfactorily the surface defect densities and their impact on the growth process, as observed by in situ and real-time dangling-bond density measurements using electron spin resonance ͑ESR͒ by Yamasaki et al 13 and high-sensitivity evanescent wave cavity ring-down spectroscopy by Aarts et al; 14 according to these measurements, the dangling-bond creation rate is lower than the actual a-Si:H growth rate.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Kinetic Monte Carlo simulations of surface growth during plasma deposition of silicon thin films

Pandey

Singh

Maroudas

2009

The Journal of Chemical Physics

View full text Add to dashboard Cite

Based on an atomically detailed surface growth model, we have performed kinetic Monte Carlo ͑KMC͒ simulations to determine the surface chemical composition of plasma deposited hydrogenated amorphous silicon ͑a-Si:H͒ thin films as a function of substrate temperature. Our surface growth kinetic model consists of a combination of various surface rate processes, including silyl ͑SiH 3 ͒ radical chemisorption onto surface dangling bonds or insertion into Si-Si surface bonds, SiH 3 physisorption, SiH 3 surface diffusion, abstraction of surface H by SiH 3 radicals, surface hydride dissociation reactions, as well as desorption of SiH 3 , SiH 4 , and Si 2 H 6 species into the gas phase. Transition rates for the adsorption, surface reaction and diffusion, and desorption processes accounted for in the KMC simulations are based on first-principles density-functional-theory computations of the corresponding optimal pathways on the H-terminated Si͑001͒-͑2 ϫ 1͒ surface. Results are reported for two types of KMC simulations. The first employs a fully ab initio database of activation energy barriers for the surface rate processes involved and is appropriate for modeling the early stages of growth. The second uses approximate rates for all the relevant processes to account properly for the effects on the activation energetics of interactions between species adsorbed at neighboring surface sites and is appropriate to model later stages of growth toward a steady state of the surface composition. The KMC predictions for the temperature dependence of the surface concentration of SiH x͑s͒ ͑x =1,2,3͒ species, the surface hydrogen content, and the surface dangling-bond coverage are compared to experimental measurements on a-Si:H films deposited under operating conditions for which the SiH 3 radical is the dominant deposition precursor. The predictions of both KMC simulation types are consistent with the reported experimental data, which are based on in situ attenuated total reflection Fourier transformed infrared spectroscopy.

show abstract

Section: -6mentioning

confidence: 76%

Section: Introductionmentioning

confidence: 99%

Kinetic Monte Carlo simulations of surface growth during plasma deposition of silicon thin films

Pandey

Singh

Maroudas

2009

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…The surface radical sites (the so-called dangling bonds) are generally believed to be growth sites for the thin film; the absorption of these surface dangling bonds, as well as of bulk dangling bonds, was probed with the folded resonator. It has been shown that the creation rate of the surface dangling bond during thin-film growth was 60 times too small to account for the actual growth rate (87).…”

Section: Evanescent-wave Cavity Ring-down Spectroscopy Using Folded Rmentioning

confidence: 99%

“…The same folded resonator with mirror coatings centered at 1205 nm has been utilized as an in situ probe for measuring dangling bond defects during growth of a hydrogenated amorphous silicon (a-Si:H) thin film on the TIR surface of the resonator (87). Such films play an important role in the development of low-cost flexible solar cells, but mechanistic insight into the exact growth mechanism of the deposited films is limited.…”

Section: Evanescent-wave Cavity Ring-down Spectroscopy Using Folded Rmentioning

confidence: 99%

Liquid-Phase and Evanescent-Wave Cavity Ring-Down Spectroscopy in Analytical Chemistry

Sneppen

Ariese

Gooijer

et al. 2009

Annual Rev. Anal. Chem.

View full text Add to dashboard Cite

Due to its simplicity, versatility, and straightforward interpretation into absolute concentrations, molecular absorbance detection is widely used in liquidphase analytical chemistry. Because this method is inherently less sensitive than zero-background techniques such as fluorescence detection, alternative, more sensitive measurement principles are being explored. This review discusses one of these: cavity ring-down spectroscopy (CRDS). Advantages of this technique include its long measurement pathlength and its insensitivity to light-source-intensity fluctuations. CRDS is already a wellestablished technique in the gas phase, so we focus on two new modes: liquidphase CRDS and evanescent-wave (EW)-CRDS. Applications of liquidphase CRDS in analytical chemistry focus on improving the sensitivity of absorbance detection in liquid chromatography. Currently, EW-CRDS is still in early stages: It is used to study basic interactions between molecules and silica surfaces. However, in the future this method may be used to develop, for instance, biosensors with high specificity.

show abstract

“…As O-H and C-H groups have been observed in the Er-doped Y 2 O 3 , an attempt was made to detect these species by CRDS by probing possible overtone and combination modes of O-H and C-H vibrations. Recently, CRDS in the evanescent-wave configuration 46,47 ͑EW-CRDS͒ was found to be highly sensitive for the detection of C-H overtones of surface adsorbed chloroethylenes, 48 surface Si dangling bonds in amorphous hydrogenated silicon ͑a-Si:H͒ films, 49 and O-H combination bands on amorphous SiO 2 . 50 Using the linear cavity in the current experiments, no absorption peaks could be observed in the wavelength region of 1000-1125 nm; however, an absorption peak could be clearly observed between 1360 and 1400 nm for the second wavelength scan, as shown in Fig.…”

Section: Quantification Of Oh and Chmentioning

confidence: 99%

Optical properties of Y2O3 thin films doped with spatially controlled Er3+ by atomic layer deposition

Hoang¹,

Van²,

Sawkar-Mathur³

et al. 2007

Journal of Applied Physics

Self Cite

View full text Add to dashboard Cite

Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers)Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. We report in this work the optical properties of Er 3+ -doped Y 2 O 3 , deposited by radical enhanced atomic layer deposition. Specifically, the 1.53 m absorption cross section of Er 3+ in Y 2 O 3 was measured by cavity ring-down spectroscopy to be ͑1.9± 0.5͒ ϫ 10 −20 cm 2 , about two times that for Er 3+ in SiO 2 . This is consistent with the larger Er 3+ effective absorption cross section at 488 nm, determined based on the 1.53 m photoluminescence yield as a function of the pump power. X-ray photoelectron spectroscopy and Rutherford backscattering spectroscopy were used to determine the film composition, which in turn was used to analyze the extended x-ray absorption fine structure data, showing that Er was locally coordinated to only O in the first shell and its second shell was a mixture of Y and Er. These results demonstrated that the optical properties of Er 3+ -doped Y 2 O 3 are enhanced, likely due to the fully oxygen coordinated, spatially controlled, and uniformly distributed Er 3+ dopants in the host. These findings are likely universal in rare-earth doped oxide materials, making it possible to design materials with improved optical properties for their use in optoelectronic devices.

show abstract

Absolute in situ measurement of surface dangling bonds during a-Si:H growth

Cited by 20 publications

References 20 publications

Kinetic Monte Carlo simulations of surface growth during plasma deposition of silicon thin films

Kinetic Monte Carlo simulations of surface growth during plasma deposition of silicon thin films

Liquid-Phase and Evanescent-Wave Cavity Ring-Down Spectroscopy in Analytical Chemistry

Optical properties of Y2O3 thin films doped with spatially controlled Er3+ by atomic layer deposition

Contact Info

Product

Resources

About