Absorption Of Thin Films Research Articles

Image sensors using thin-film absorbers.

Image sensors are must-have components of most consumer electronics devices. They enable portable camera systems, which find their way into billions of devices annually. Such high volumes are possible thanks to the complementary metal-oxide semiconductor (CMOS) platform, leveraging wafer-scale manufacturing. Silicon photodiodes, at the core of CMOS image sensors, are perfectly suited to replicate human vision. Thin-film absorbers are an alternative family of photoactive materials, distinguished by the layer thickness comparable with or smaller than the wavelength of interest. They allow design of imagers with functionalities beyond Si-based sensors, such as transparency or detectivity at wavelengths above Si cutoff (e.g.,short-wave infrared). Thin-film image sensors are an emerging device category. While intensive research is ongoing to achieve sufficient performance of thin-film photodetectors, to our best knowledge, there have been few complete studies on their integration into advanced systems. In this paper, we will describe several types of image sensors being developed at imec, based on organic, quantum dot, and perovskite photodiode and show their figures of merit. We also discuss the methodology for selecting the most appropriate sensor architecture (integration with thin-film transistor or CMOS). Application examples based on imec proof-of-concept sensors are demonstrated to showcase emerging use cases.

Design of a broadband solar absorber based on Fe2O3/CuO thin film absorption structure

Design of a broadband solar absorber based on Fe2O3/CuO thin film absorption structure

Optical and morphological properties of Ge-incorporated polycrystalline Sb2Se3 thin-film for photovoltaic applications

Crystalline Ge-incorporated Sb2Se3 thin-films are the promising absorber material for third-generation solar cells due to its optical, electrical, and material properties with earth-abundant materials. In this contribution, we have grown polycrystalline Ge-incorporated Sb2Se3 thin-film absorbers and conducted morphological and optical analysis by Scanning Electron Microscopy and UV–Vis spectroscopy along with the chemical structure analysis with Raman Spectroscopy for photovoltaic absorber applications. Ge-incorporated Sb2Se3 thin-films were deposited with Vapor Transport Deposition techniques, using thermally evaporated Sb2Se3 and Ge from each Sb2Se3 and Ge nanopowder source as precursors. Evaporation temperatures of Sb2Se3 and Ge nanopowder sources were independently controlled in the different heating zones of the furnace. At the deposition temperature of 300 °C, grains of Ge-incorporated Sb2Se3 thin-film begin to grow due to the increased crystallization temperature by Ge incorporation. With temperature-dependent absorption spectrum and the indirect optical transition natures, the optical bandgap of Ge-incorporated Sb2Se3 absorbers is extracted as 1.15 eV and 1.23 eV for samples grown at 500 °C and 520 °C.

Control of the Organization of 4,4′-bis(carbazole)-1,1′-biphenyl (CBP) Molecular Materials through Siloxane Functionalization

We show that through the introduction of short dimethylsiloxane chains, it was possible to suppress the crystalline state of CBP in favor of various types of organization, transitioning from a soft crystal to a fluid liquid crystal mesophase, then to a liquid state. Characterized by X-ray scattering, all organizations reveal a similar layered configuration in which layers of edge-on lying CBP cores alternate with siloxane. The difference between all CBP organizations essentially lay on the regularity of the molecular packing that modulates the interactions of neighboring conjugated cores. As a result, the materials show quite different thin film absorption and emission properties, which could be correlated to the features of the chemical architectures and the molecular organizations.

Nanobelt and nanoplatelet structured molybdenum disulfide thin film as a saturable absorber under nanopulsed green laser excitation

Demonstration of saturable absorption (SA) in MoS2 thin films with varying NLO coefficients as a function of reaction time of hydrothermal method is made using the open aperture Z-scan technique. Under nanosecond pulsed laser excitation (532 ​nm, 9 ns, 10 HZ), saturable absorption occurred involving the overtone of electron - hole pair state and band edge state of MoS2. Further higher ground state cross-section than excited state cross-section favors SA process in MoS2 thin films. The strong saturable absorption behaviors of nanobelt like structured MoS2 film could be attributed to the coexistence of 1T and 2H crystal phases and lower dimension morphology that allows more photons to transit to the higher energy state. Earlier the fabrication of MoS2 thin film on a FTO substrate with a varying reaction time of the hydrothermal technique such as 24, 36, 48 and 60 ​h was made. Raman spectrum has two sets of characteristics vibration representing the metallic 1T – octahedral coordination Oh phase and the semiconducting 2H – trigonal prismatic D3h phase. XRD and Raman studies confirm the formation of mixed phases of MoS2 with 1T phase dominating over 2H phase in MoS2 thin films. Here the absorbance and band gap of the MoS2 thin film increased with increase in reaction time. The luminescence spectra exhibit prominent peaks at 594 ​nm and 621 ​nm resulting from a direct bandgap transition and they are mostly due to the VBM splitting at the K-point. All the films exhibit maximum absorbance in the UV region (291 ​nm) due to the excitonic features of MoS2 and notable absorbance in the visible region (680 ​nm) due to the overtones of MoS2 ‘s electron-hole pair. SEM images confirm that nanoplatelet and nanobelt structured MoS2 was formed with varying size with respect to reaction time. Furthermore, while the nanoplatelet structure faded, nanobelts were grown for a prolonged reaction time. Thus, MoS2 nanostructure coated thin film would be useful for the design of saturable absorbers for fabricating optical switches and mode locking devices.

Effect of interfacial mixed layer on hydrogen absorption in yttrium thin films

Pd/Y bilayers and Pd/Ti/Y trilayers were prepared in a UHV chamber by DC/RF magnetron sputtering. The characterization of the Pd-Y and Ti-Y interfaces was performed immediately after the deposition using in-situ X-ray photoelectron spectroscopy (XPS). The results indicated significant interface mixing for the Pd/Y bilayers. Further studies showed that the additional Ti layer deposited between the palladium and yttrium layers can significantly reduce the mixing of the Pd-Y layers during the deposition process at room temperature, leading to the formation of a sharp Ti-Y interface. The structure of the obtained layers before and after the hydrogenation was examined by the standard X-ray diffraction method. The hydrogenation kinetics was studied in-situ at room temperature and pressure up to 1 bar using simultaneous measurements of resistivity and optical transmittance. It was found that for a thickness of Ti equal to 5 nm, the shortest transition time to the YH3 phase was obtained while maintaining a short switching time.

Thermal IR Detection With Nanoelectromechanical Silicon Nitride Trampoline Resonators

Nanoelectromechanical (NEMS) resonators are promising uncooled thermal infrared (IR) detectors to overcome existing sensitivity limits. Here, we investigated NEMS trampoline resonators made of silicon nitride (SiN) as thermal IR detectors. Trampolines have an enhanced responsivity of more than two orders of magnitude compared to state-of-the-art SiN drums. The characterized NEMS trampoline IR detectors yield a sensitivity in terms of noise equivalent power (NEP) of 7 pW/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sqrt {\text {Hz}}$ </tex-math></inline-formula> and a thermal response time as low as 4 ms. The detector area features an impedance-matched metal thin-film absorber with a spectrally flat absorption of 50% over the entire mid-IR spectral range from 1 to 25 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> .

Experimental and Theoretical Investigation of High-Resolution X-ray Absorption Spectroscopy (HR-XAS) at the Cu K-Edge for Cu2ZnSnSe4

Energy sustainability is critical for social activities in the human world. The quaternary compound Cu2ZnSnSe4 (CZTSe), as a promising candidate for thin-film solar cell absorption with medium-level thermoelectric performance, is of interest for the purpose of utilizing solar energy. The defect chemistry and atomic ordering in this particular compound also triggers interests in understanding its crystallographic structure as well as defects. Hereby, high energy resolution X-ray absorption spectroscopy is employed to investigate the electronic and geometric structural complexity in pristine and cobalt-doped Cu2ZnSnSe4. The occupational atomic sites of Cu are found to be mixed with the Zn atoms, forming CuZn anti-defects, which serve as a knob to tune local electronic structures. With proper doping, the band structure can be manipulated to improve the optical and thermoelectric properties of the CZTSe compounds.

Novel BixLa1-xMnyCo1-yO3 nanocrystalline perovskite based MIS Schottky UV photodetector device

This study introduces the fabrication of MIS junction for UV photodetection applications employing BixLa1-xMnyCo1-yO3 as an insulating layer (I-layer). The structure refinement of the synthesized perovskite powder is performed. The perovskite thin films' structural, topographical, and compositional features are inspected. The measured UV-visible optical absorption of thin films is discussed, where the energy gap and Urbach energy are estimated to be ∼3.09 eV and 93.4 meV, respectively. The MIS configuration was built employing p-silicon and Ag-electrode. The microelectronic parameters of the designed junction are calculated. The charge transport mechanism is interpreted in detail in the light of trap states. We evaluated the UV photodetection performance of the implemented device under different intestines. Some photodetection parameters have been determined, such as responsivity, detectivity, and external quantum efficiency, which yielded ∼8.01 mA/W, 1.23 × 109 cm.Hz0.5/W, and 4.32%, respectively. The engineered device showed a stable and fast response.

Evaporated Self‐Assembled Monolayer Hole Transport Layers: Lossless Interfaces in p‐i‐n Perovskite Solar Cells

AbstractEngineering of the interface between perovskite absorber thin films and charge transport layers has fueled the development of perovskite solar cells (PSCs) over the past decade. For p‐i‐n PSCs, the development and adoption of hole transport layers utilizing self‐assembled monolayers (SAM‐HTLs) based on carbazole functional groups with phosphonic acid anchoring groups has enabled almost lossless contacts, minimizing interfacial recombination to advance power conversion efficiency in single‐junction and tandem solar cells. However, so far these materials have been deposited exclusively via solution‐based methods. Here, for the first time, vacuum‐based evaporation of the most common carbazole‐based SAM‐HTLs (2PACz, MeO‐2PACz, and Me‐4PACz) is reported. X‐ray photoelectron spectroscopy and infrared spectroscopy demonstrate no observable chemical differences in the evaporated SAMs compared to solution‐processed counterparts. Consequently, the near lossless interfacial properties are either preserved or even slightly improved as demonstrated via photoluminescence measurements and an enhancement in open‐circuit voltage. Strikingly, applying evaporated SAM‐HTLs to complete PSCs demonstrates comparable performance to their solution‐processed counterparts. Furthermore, vacuum deposition is found to improve perovskite wetting and fabrication yield on previously non‐ideal materials (namely Me‐4PACz) and to display conformal and high‐quality coating of micrometer‐sized textured surfaces, improving the versatility of these materials without sacrificing their beneficial properties.

Structural, morphological, and optical studies of sol–gel spin coated TiO2 thin films

Nanoporous mesostructured Titanium dioxide [TiO2] thin films were deposited on a glass substrate by sol–gel spin coating method using Titanium tetra isopropoxide as a precursor. One set of the prepared samples was annealed at 300 °C for an hour and another set at 400 °C for an hour. The study of structural, morphological, and optical characterizations of these films was carried out using X-ray diffraction (XRD), Raman spectroscopy, FESEM, and UV–vis spectroscopy. The XRD pattern confirms the formation of the anatase phase of TiO2 nanostructured thin films. The strong Raman line at around 144 cm−1 confirms the anatase phase of the synthesized TiO2. FESEM images show plate-like TiO2 particles from micrometer to sub-micrometer size in the grown thin films. The size of the particles was found to be bigger in dimension in the 400 °C annealed TiO2 thin films than in 300 °C annealed TiO2 thin films. The UV–visible optical absorption studies show high optical absorption in TiO2 thin films in the visible region of the electromagnetic spectrum.

Simultaneous electrical impedance and optical absorption spectroscopy for rapid characterization of oxygen vacancies and small polarons in doped ceria.

Mixed ionic-electronic conductors (MIECs) play a central role in emerging energy conversion and energy efficient computational technologies. However, it is both challenging and resource demanding to characterize MIECs over the broad range of experimental conditions of interest, thereby significantly limiting their study and applications. Here, a novel method of a simultaneous measurement of electrical conductivity and optical absorption of thin films in out-of-equilibrium state, i.e. during a reduction process, is employed for a comprehensive study of a MIEC oxide, PrxCe1-xO2-δ (PCO). It enables, orders of magnitude faster than by established techniques, characterization of the oxygen vacancy and small polaron formation and transport as a function of temperature (demonstrated here down to 200 °C), in a wide range of deviation from stoichiometry, δ. For instance, at 600 °C the PCO properties were obtained during a ten minute reduction process, in the pO2 range from 1 to 10-13 bar. The experimental results show that the oxygen vacancy mobility is constant while the small polaron mobility is linear in δ, in the whole pO2 range, which yields the total conductivity quadratic in δ. Furthermore, the method was applied to study the modification of PCO's transport properties with composition change. It was shown that increasing x from 0.1 to 0.2 suppresses the ionic mobility and, at the same time, enhances the small polaron mobility. Finally, the optically determined δ was used to define an instantaneous oxygen activity in PCO that can be accessed in the out-of-equilibrium experiments. This work opens up new possibilities to study the effects of microstructure, strain and other applied external stimuli on the transport and thermodynamic properties of PCO and similar types of MIEC materials.

2D Chalcogenide Thin Films for Super-Resolved Laser Structuring

The saturable absorption behaviour associated with chalcogenide thin films has been investigated and optimized using Z-Scan Technique. Huge saturable absorption responses (of the order of 10^-7 m/W) were observed for the Bismuth Selenide thin films, which depend on material characteristics and the laser parameters. An approach in which the application of the saturable absorber thin films for super-resolved laser inscriptions has been discussed and a theoretical analysis of the super-resolution efficiency of the thin films has been made.

Enhanced photoresponse of Cu2ZnSnS4 absorber thin films fabricated using multi-metallic stacked nanolayers.

Cu2ZnSnS4 (CZTS) thin films have attracted considerable attention as potential candidates for photovoltaic absorber materials. In a vacuum deposition technique, a sputtering stacked metallic layer followed by a thermal process for sulfur incorporation is used to obtain high-quality CZTS thin films. In this work, for fabricating CZTS thin films, we have done a 3LYS (3 layers), 6LYS, and 9LYS sequential deposition of Sn/ZnS/Cu metal stack (via. metallic stacked nanolayer precursors) onto Mo-coated corning glass substrate via. RF-sputtering. The prepared thin films were sulfurized in a tubular furnace at 550 °C in a gas mixture of 5% H2S + 95% Ar for 10 min. We further investigated the impact of the Sn/ZnS/Cu metal stacking layers on the quality of the thin film based on its response to light because metal inter-diffusion during sulfurization is unavoidable. The inter-diffusion of precursors is low in a 3-layer stack sample, limiting the fabricated film's performance. CZTS films with 6-layer and 9-layer stacks result in an improved photocurrent density of ∼38 μA cm-2 and ∼82 μA cm-2, respectively, compared to a 3-layer sample which has a photocurrent density of ∼19 μA cm-2. This enhancement can be attributed to the 9-layer approach's superior inter-diffusion of metallic precursors and compact, smooth CZTS microstructure evolution.

High performance amorphous Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; thin film solar blind ultraviolet photodetectors decorated with Al nanoparticles

Gallium oxide (Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;) as a wide bandgap semiconductor material has attracted much attention in the field of solar blind ultraviolet photodetection recently. Localized surface plasmon resonance is considered an effective way to improve the performance of optoelectronic devices by decorating the materials with metal particles. Al nanoparticle is a potential candidate for ultraviolet photodetectors because its suitable resonance wavelength is located in the ultraviolet wavelength range. In this work, the preparation temperature of the Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; thin film is reduced by ultraviolet photo-annealing, and the amorphous Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; thin film is prepared by using the solution method. In addition, aluminum (Al) nanoparticles are used to decorate the surface of Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; thin film through thermal evaporation of aluminum film and then annealing, which improves the optoelectrical performance in the solar-blind wavelength spectrum. The X-ray diffraction (XRD) is employed to demonstrate the amorphous Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; thin film. The surface roughness and the diameters of Al nanoparticles are analyzed by atomic force microscope (AFM). When the thickness of the deposited Al layer is about 3–5 nm, Al particles with the diameters in a range of 2–3 nm can be obtained. When the thickness of the deposited Al layer is more than 7 nm, Al nanoparticles turn into the particles with non-identical diameters and distribute in the form of agglomeration. Transmittance spectrum and absorption spectrum are employed to characterize the optical properties. The bandgaps of different samples are obtained, and the results are consistent with the theoretical ones. The Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; thin film shows excellent optoelectrical performance and solar blind rejection ratio. Under 254 nm illumination, the maximum photo-to-dark current ratio is 2.55×10&lt;sup&gt;4&lt;/sup&gt;, and the rejection ratio of &lt;i&gt;I&lt;/i&gt;&lt;sub&gt;254 nm&lt;/sub&gt;/&lt;i&gt;I&lt;/i&gt;&lt;sub&gt;365 nm&lt;/sub&gt; is 2.2×10&lt;sup&gt;4&lt;/sup&gt;. The best responsivity and detectivity of prepared samples are 0.771 A/W and 1.13×10&lt;sup&gt;11&lt;/sup&gt; Jones, which are about 34 times and 36 times higher than those without Al decoration. The improvement is attributed to the scattering effect of surface Al nanoparticles for illumination, which enhances the Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; thin film absorption of solar blind ultraviolet light. Meanwhile, owing to the localized surface plasma resonance, the local electromagnetic fields generated near the Al nanoparticles promote the transfer of carriers in the film. Furthermore, the point about how the Al nanoparticles decorated on the surface of Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; thin film influence the time response is also discussed in this work. As a result, the introduction of defect states will lead to an increase of fall time due to the Al deposition. In this work, the effect of Al nanoparticles decoration on the optoelectrical performance of amorphous Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; thin film solar blind ultraviolet photodetectors is studied based on a simple preparation, which provides a possible pathway for developing the flexible solar blind electronic devices in the future.

Giant saturation absorption of tungsten trioxide film prepared based on the seedless layer hydrothermal method

Nonlinear materials have gained wide interest as saturable absorbers and pulse compression for pulsed laser applications due to their unique optical properties. This work investigates the third-order nonlinear phenomenon of tungsten trioxide (WO3) thin films. The giant nonlinear absorption and nonlinear refractive index of WO3 thin films were characterized by Z-scan method at 800 nm. We experimentally observed the giant saturable absorption (SA) and nonlinear refractive index of WO3 thin films prepared by the seedless layer hydrothermal method, with SA coefficient being as high as –2.59 × 105 cm⋅GW−1. The SA coefficient is at least one order of magnitude larger than those of the conventional semiconductors. The nonlinear refractive index n 2 of WO3 film has been observed for the first time in recent studies and the corresponding coefficient can be up to 1.793 cm2⋅GW−1. The large third-order nonlinear optical (NLO) response enables WO3 thin films to be promising candidates for optoelectronic and photonic applications in the near-infrared domain.

Effect of oxygen defects on microstructure, optical and vibrational properties of ScN films deposited on MgO substrate from experiment and first principles

We report on the effects of oxygen impurities on the microstructure, surface morphology, optical absorption, and vibrational properties of scandium nitride thin films deposited onto magnesium oxide substrate by reactive magnetron sputtering and under ultrahigh vacuum conditions. Two distinct deposition temperatures of 700°C and 800°C were applied to adjust the level of oxygen contamination. The ScN/MgO(001) thin films have been characterized by various spectroscopic methods, including X-ray diffraction, X-ray photoelectron spectroscopy, atomic force microscopy, Raman spectroscopy, and optical microscopy. The ScN films deposited at the lower temperature of the MgO substrate show higher content of defects, stronger disorientation, a larger concentration of twin domains, and suppressed adatom mobility as compared to layers deposited at the higher temperature. An increase by 2% in the amount of accommodated oxygen results in the increase in the direct energy gap of the ScN films by about 0.13 eV, which follows from the increased concentration of the n-type charge carriers incorporated by oxygen impurities. The observed increase in the absorption edge, i.e., enlargement of the optical band gap can be accounted for the Burstein–Moss effect. Experimental Raman spectra reveal coupling between longitudinal optic phonons and electronic states, which can be described by the Fano-type function with the asymmetry parameter increasing with increased content of oxygen defects. The ab initio Raman spectra of ScN with concentrations of oxygen impurities corresponding to the respective experimental values, obtained within density functional theory, demonstrate that incorporated impurities affect significantly the phonon dynamics via modified force constants, including those at atoms beyond the nearest neighbors of defects. The simulated Raman spectra reflect major features of the experimentally determined spectral patterns enabling better insight into the origin of changes experienced by the oxygen-modified ScN/MgO(001) films.

Electric field tuning of the optical absorbance of topological insulator thin films

In view of electro-optic modulators and switches operating in the terahertz frequency range, we study the absorbance of a topological insulator (TI) thin film subjected to a static electric field. Adopting the Hamiltonian for the three-dimensional ${\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$ class of TIs including terms to second order in the electron wave vector and to first order in the electric field, we present an effective model for a TI thin film. We demonstrate the distinct influences of in-plane and out-of-plane external electric fields, the in-plane electric field-induced dichroism, and the electric field and chemical potential tuning of the absorbance edge. Under the influence of an out-of-plane electric field, a TI film with a thickness of about 2 nm exhibits a considerable absorbance at the absorbance edge. Of prime practical importance, the absorbance edge can be shifted about $0.3\phantom{\rule{0.28em}{0ex}}\mathrm{eV}$ with the application of moderate electric fields about $0.4\phantom{\rule{0.28em}{0ex}}\mathrm{V}{\mathrm{nm}}^{\ensuremath{-}1}$ or with chemical potential variations about $0.3\phantom{\rule{0.28em}{0ex}}\mathrm{eV}$.

Effect of Argon on the Properties of Copper Nitride Fabricated by Magnetron Sputtering for the Next Generation of Solar Absorbers.

Copper nitride, a metastable semiconductor material with high stability at room temperature, is attracting considerable attention as a potential next-generation earth-abundant thin-film solar absorber. Moreover, its non-toxicity makes it an interesting eco-friendly material. In this work, copper nitride films were fabricated using reactive radio frequency (RF) magnetron sputtering at room temperature, 50 W of RF power, and partial nitrogen pressures of 0.8 and 1.0 on glass and silicon substrates. The role of argon in both the microstructure and the optoelectronic properties of the films was investigated with the aim of achieving a low-cost absorber material with suitable properties to replace the conventional silicon in solar cells. The results showed a change in the preferential orientation from (100) to (111) planes when argon was introduced in the sputtering process. Additionally, no structural changes were observed in the films deposited in a pure nitrogen environment. Fourier transform infrared (FTIR) spectroscopy measurements confirmed the presence of Cu-N bonds, regardless of the gas environment used, and XPS indicated that the material was mainly N-rich. Finally, optical properties such as band gap energy and refractive index were assessed to establish the capability of this material as a solar absorber. The direct and indirect band gap energies were evaluated and found to be in the range of 1.70-1.90 eV and 1.05-1.65 eV, respectively, highlighting a slight blue shift when the films were deposited in the mixed gaseous environment as the total pressure increased.

Photophysical and optical properties of 4-(4'-(diphenylamino)benzylidene)-2-phenyloxazol-5(4H)-ones induced by the peripheral substituent

Photophysical and optical properties of 4-(4'-(diphenylamino)benzylidene)-2-phenyloxazol-5(4H)-ones differing in the peripheral substituent have been investigated in chloroform, solvent mixture, polymer matrix and solid state. These properties are influenced by the nature of the substituent on the phenyl ring and the environment. The dye bearing phenyl group or without substituent in para position of the phenyl group in 2-phenyloxazol-5(4H)-one moiety has the brightest emission in a solid state, whereas the dye with cyano functional group possesses the strongest emission in chloroform. The spectral behavior of the tested dyes is dependent on the solvent mixture. The fluorescence of the oxazolone dye in CHCl3/MeOH was reduced due to hydrogen bond formation, whereas addition of water to the THF or DMSO indicate the enhancement in emission caused by aggregation induced emission (AIE). The absorption and fluorescence spectra of the oxazolone polymer thin film are shifted to blue compared to the dyes dissolved in chloroform.The surface topography of the oxazolone thin films was examined using atomic force microscopy (AFM). The optical properties of the dye layers and dyes immobilized in PMMA matrix were determined by spectroscopic ellipsometry (SE). The absorption coefficient, refractive index, extinction coefficient and the energy bandgap can be effectively manipulated by changing substituent in the dye structure.