A. Korcala

Optical properties of metallophthalocyanine compounds thin films

This work contains investigation results of the linear and nonlinear optical properties of metallophthalocyanines (Cu, Co, Zn, and Mg) and metallophthalocyanine chlorides (Al, Ga) thin films which were grown by physical vapor deposition (PVD) technique in high vacuum on transparent (quartz) and semiconductor (silica) substrates. Spectral properties of these films were examined using transmission, SGH and THG technique. Structural properties were investigated by AFM measurements. Transmission spectra were shown a large influence of intermolecular interaction on spectral properties of metallophthalocyanines and metallophthalocyanine chlorides. The influence of films thickness and annealing process of samples on their optical properties were also determined. The thickness dependence was connected with morphology of the film while annealing was caused change in polymorph phase. The measurements of transmission, SHG and THG spectra were allowed to determine optical constant of these films.

Photoluminescence of electrochemically etched porous silicon coated with small-molecule based thin organic films

In this paper, photoluminescence (PL) spectra of porous silicon (PSi) prepared by electrochemical anodisation coated with small-molecule based thin organic films are presented. Thin layers of copper phthalocyanine (CuPc) and tris(8-hydroxyquinoline) aluminium (Alq3) were deposited on PSi using the conventional thermal evaporation in high vacuum. Presented structures exhibit strong photoluminescence in visible region at room temperature under pulsed UV excitation. PL spectra of Alq3 deposited on glass and PSi layer without organic film are presented for intercomparison. The shapes of PL spectra of PSi/organic structures depends on material used and exhibit multiband structure. Properties of PSi/organic luminescence can be explained by penetration of organic material into PSi skeleton and interaction between carriers in PSi and deposited material.

Study of ZnO thin film deposited by PVD

We present structural and optical properties of ZnO thin films deposited by using Pulsed Laser Deposition (PVD) technique on quartz substrates. The deposition process was carried out at various temperatures of the substrates from room temperature (RT) to 825K in order to investigate these properties of the films and their mutual influence. The structural and morphological properties of the films were investigated Atomic Force Microscopy measurements, respectively. The quality of the films was improved with an increase of the substrate temperature. Classic photoluminescence measurement allowed us to estimate band gap energy as a function of the temperature. Experimental spectra confirm high structural and linear optical quality of investigated films.

Pulsed laser deposition of hafnium oxide on quartz substrate

In this paper, we report the experimental investigation of optical properties of HfO2 (hafnium oxide) thin films grown on quartz substrates by pulsed laser deposition (PLD) method [1]. Cold pressed powders of hafnium oxide (HfO2 98% - Aldrich Chem. Co.) were used as the target for deposition process. The transparent quartz substrate was heated up to temperature in the range between 200 and 600 °C. Optical properties of the films were investigated by transmittance in the ultra-violet, visible and near infrared range and photoluminescence spectroscopy. We measure the photo-luminescence spectra and dynamics of luminescence process [2]. The PL spectra contained one strong maximum at 385 nm and the peak intensity decreases rapidly with increasing temperature. Optical properties are closely related to the structure of the hafnium oxide thin films.

Study of photoadmittance and admittance of porous silicon layers

In this work, we investigated electrical properties of Al/PS/p-Si structures. Admittance spectroscopy is one of the major semiconductor diagnostic techniques. Frequency, voltage and wavelengths dependencies of admittance will be analyzed in detail. It will be useful for better understanding of fundamental electrical properties of porous silicon.

DC and AC conductivity of PbSe/Si structures grown by pulsed laser ablation methods

In this paper we report the result of investigation of the electrical transport in PLD grown n-PbSe/n-Si heterojunction by DC and AC current measurement techniques. This characterization method is a well-suited and simple technique to study the interface between two semiconductors. The Si substrates are highly doped (ρ = 0.45 Ωcm), and consequently most of the heterojunction depletion layer falls in the PbSe epilayer. Fabrication of PbSe thin films on Si substrates by the pulsed laser deposition(PLD) method has been demonstrated. The films were characterized by X-ray diffraction analysis.

Pulsed laser deposition (PLD) of hafnium oxide thin films

This work contains the experimental investigation of optical properties of HfO2 (hafnium oxide) thin films grown on quartz and n-type silica substrates by pulsed laser deposition method. Cold pressed powders of hafnium oxide (HfO2 98% - Aldrich Chem. Co.) were used as the target for deposition process. The substrates was heated up to temperature in the range between 200 and 500 °C. Optical properties of the films were investigated by transmittance in the ultra-violet, visible and near infrared range and photoluminescence spectroscopy. We measure the photo-luminescence spectra and dynamics of luminescence process. Optical properties are closely related to the structure of the hafnium oxide thin films.

Photoluminescence of MgO thin films on Si (111) substrate, prepared by sol-gel method

Here we present the results of the measurements of photoluminescence properties of thin films of MgO (magnesium oxide) on Si substrate (mono-crystalline (111) silicon). The samples were prepared by the sol-gel method that is very simple method for fabrication metal oxide layers on different kind of substrates. We carried out the photoluminescence experiments at a wide range of temperatures from 10 to 300 K. We summarize how shape complexity of registered spectra depends on the temperature and the preparation conditions.

Investigations of temperature dependent photoluminescence process in MgO thin films

Pulsed laser deposition (PLD) technique (called also laser ablation) has been employed to grow magnesium oxide thin films on quartz wafers. The optical properties of MgO thin films were studied using temperature dependent photoluminescence measurements. The structural properties of the MgO thin films were carried out using X-ray method. A strong dependence of the films structure, the crystalline quality and the optical properties of investigated films caused by variation of substrates temperature was observed.

Photoluminescence of ZnO thin films on Si substrate

In this paper photoluminescence (PL) properties of ZnO (zinc oxide) thin films on Si substrates are presented. Samples were prepared by sol-gel method. Photoluminescence experiments where carried out at different temperatures (10 K- 300 K). Registered spectra exhibit multiband structure witch depends on the temperature and preparation conditions.