The work presents the results of a research carried out with Plasmalab Plus 100 system, manufactured by Oxford
Instruments Company. The system was configured for deposition of diamond-like carbon films by ICP PECVD method.
The deposition processes were carried out in CH<sub>4</sub> or CH<sub>4</sub>/H<sub>2</sub> atmosphere and the state of the plasma was investigated by
the OES method. The RF plasma was capacitively coupled by 13.56 MHz generator with supporting ICP generator
(13.56 Mhz). The deposition processes were conducted in constant value of RF generator’s power and resultant value of
the DC Bias. The power values of RF generator was set at 70 W and the power values of ICP generator was set at 300
W. In this work we focus on the influence of DLC film’s thickness on optical, electrical and structural properties of the
deposited DLC films. The quality of deposited DLC layers was examined by the Raman spectroscopy, AFM microscopy
and spectroscopic ellipsometry. In the investigated DLC films the calculated sp<sup>3</sup> content was ranging from 60 % to 70 %.
The films were characterized by the refractive index ranging from 2.03 to 2.1 and extinction coefficient ranging from
0.09 to 0.12.
Semiconductors containing so-called DX centers exhibit at low temperatures an ability to modify locally a refractive index under illumination. This modification persists due to the metastable character of the centers. As a result at low temperatures persistent photoeffects are observed for the materials. This property suggests the potential application of the materials in optoelectronic devices and an optical memory based on holography. It has been shown that at low temperatures the centers behave like deep defects whereas after photoionization they behave like shallow dopants. This twofold nature also accompanies different localization at the crystal lattice. As a result at low temperatures return to the "dark" ground state is not possible unless the system possesses enough energy. This energy is called the capture barrier. Changes in the refractive index depend on the height of the capture barrier and temperature. Estimation of the barrier is therefore of prime importance for materials possessing DX centers. It was found that a gallium dopant in Cd<sub>1-x</sub>Mn<sub>x</sub>Te exhibits DX-like behaviour. In this paper we report on the capture barrier of gallium doped Cd<sub>0.99</sub>Mn<sub>0.01</sub>Te. In order to determine the barrier persistent photoconductivity (PPC) decay kinetics were investigated. The kinetics are governed by the transition from a shallow donor state to the deep DX state. The measurements were run within a temperature range from 77K<T<105K. The capture barrier was deduced from the decay time constants after switching off the light taken at different temperatures. Its value was found to be equal to 0.23eV.