Infrared Absorption Study of Zn–S Hybrid and ZnS Ultrathin Films Deposited on Porous AAO Ceramic Support

Abstract

Infrared (IR) spectroscopy is a powerful technique to characterize the chemical structure and dynamics of various types of samples. However, the signal-to-noise-ratio drops rapidly when the sample thickness gets much smaller than penetration depth, which is proportional to wavelength. This poses serious problems in analysis of thin films. In this work, an approach is demonstrated to overcome these problems. It is shown that a standard IR spectroscopy can be successfully employed to study the structure and composition of films as thin as 20 nm, when the layers were grown on porous substrates with a well-developed surface area. In contrast to IR spectra of the films deposited on flat Si substrates, the IR spectra of the same films but deposited on porous ceramic support show distinct bands that enabled reliable chemical analysis. The analysis of Zn-S ultrathin films synthesized by atomic layer deposition (ALD) from diethylzinc (DEZ) and 1,5-pentanedithiol (PDT) as precursors of Zn and S, respectively, served as proof of concept. However, the approach presented in this study can be applied to analysis of any ultrathin film deposited on target substrate and simultaneously on porous support, where the latter sample would be a reference sample dedicated for IR analysis of this film.

Three‐dimensional‐poly(lactic acid) scaffolds coated with gelatin/magnesium‐doped nano‐hydroxyapatite for bone tissue engineering

“…[ 28 ] Overall, in the three‐dimensional‐PLA/Gel/Mg‐nHAp composite scaffolds, all main matching characteristic peaks of individual compounds were present, and the development of an extra peak at 2361 cm ‐1 was attributed to the presence of background gaseous CO 2 in the spectrometer (Figure S3A). [ 29 ] The crystallinity of PLA, Gel, nHAp, Mg‐nHAp, and three‐dimensional‐PLA/Gel/Mg‐nHAp composite scaffolds was assessed by XRD (Figure S3B). The XRD patterns of pure PLA and Gel exhibited their characteristic peaks at the 20 values between 0° and 30° indicating their semi‐crystalline nature.…”

Fabrication of Porous Anodic Alumina (PAA) by High-Temperature Pulse-Anodization: Tuning the Optical Characteristics of PAA-Based DBR in the NIR-MIR Region

“…The resonance peaks were assigned to different orders of a given stop band based on the Bragg-Snell equation [ 30 ], assuming the angle of incidence θ ~ 0 ( λ i , i = 1–4, correspond to 1–4 orders of PSB). The broad peak at around 3000 nm, present in all spectra and marked by vertical, black, dotted line, originate from the OH group vibrations of adsorbed water [ 31 ].…”

Influence of Anodization Temperature on Geometrical and Optical Properties of Porous Anodic Alumina(PAA)-Based Photonic Structures

“… i a ( t ) curves recorded during pulse anodization (U H = 50 V with t H = 360 s, U L = 20 V with t L = 480 s, 20 cycles, at 30 °C) with decreasing U H –˃ U L drop rate form 0.078 V/s down to 0.312 V/s ( a ), the corresponding transmission spectra (the broad peak at around 3000 nm present in all spectra and marked by vertical, black, dotted line, originate from OH group vibrations of adsorbed water [ 49 ]) ( b ). …”

“…Figure 5. Transmittance spectra of PAA-based photonic structures anodized at temperature range 5-30 • C (the broad peak at around 3000 nm, present in all spectra and marked by vertical, black, dotted line, originate from OH group vibrations of adsorbed water[49]). …”