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Pure GaAs and GaAs1−xBix alloys with different Bi ratios (1 %, 2.5 %, 3.5 %) fitted with silver contacts were measured with a dielectric spectroscopy device. Dielectric characterization was performed at room temperature in the frequency range of 0.1 Hz to 1 MHz. GaAs exhibits three relaxation regions corresponding to space-charge, dipolar and ionic polarizations in sequence with increasing frequency while GaAs1−xBix samples show only a broad dipolar polarization in the same frequency range. This result proves the filling of the lattice with Bi through making a new bonding reducing the influence of ionic polarization. This finding supports the previous results concerning optical properties of GaAs1−xBix, presented in the literature. [ABSTRACT FROM AUTHOR]

Bulk TlGaS 2 single crystals were produced by the Bridgman method. TlGaS 2 thin film samples were deposited from bulk crystals by the thermal evaporation technique under a high vacuum. TlGaS 2 thin films were deposited in the 100–750 nm thickness range. Dielectric spectroscopy measurements were operated in the frequency range of 1–105 Hz and temperature range of 273–373 K under the voltage of 1 V (rms). TlGaS 2 thin films have amorphous. Bulk TlGaS 2 has a crystalline structure based on X-Ray diffraction patterns. Three polarization mechanisms were detected from the analysis of Cole-Cole plots. At low frequencies, the effect of interfacial polarization was observed. Toward higher frequencies, two dipolar polarization mechanisms were detected. In comparison to the bulk TlGaS 2 single crystal, the dielectric constant of the thin films has 100–1000 times larger values at frequencies lower than 100 Hz. The thickness limit at which bulk physical properties started has been investigated. The transition thickness between bulk/thin film properties was detected at around 700 nm. The low dielectric constant and the good conductivity around 10−8 S/cm at105 Hz can give opportunities to use these thin films in technological applications. • The interfacial polarization is observed at frequencies lower than 100 Hz. • At higher frequencies, polarization mechanisms having dipolar nature are detected. • At frequencies below 100 Hz, the dielectric constant has 100–1000 times greater values for TlGaS 2 thin films. • The dielectric properties of TlGaS 2 thin films change to bulk dielectric properties with thickness-independent dielectric behavior at 800 nm. • TlGaS 2 thin films are suitable for nano-sized switching and thermoelectric applications. [ABSTRACT FROM AUTHOR]