Growth and structural characterization of ScN/CrN periodic and quasi-periodic superlattices for thermoelectric application

Abstract: The aim of this diploma work is the deposition and characterization of ScN/CrN superlattices with both periodic and quasi-periodic structures. ScN as semiconductor material with (2eV) band gap energy was selected due to its thermal and mechanical stability and its hardness. High resistivity against oxidation and high wear resistance were the reasons for choosing CrN as another candidate for the superlattices. The Rudin Shapiro structure was selected as quasi-periodic structure because of its more random structure. In this research both periodic and Rudin Shapiro as quasi-periodic structures have been deposited and investigated. The best optimized temperature for the deposition was 835°C and the selected periodic thickness was 6 nm for periodic structure with each ScN and CrN layers having each a thickness of 3 nm. The material ratio of Rudin Shapiro superlattices was kept the same as periodic samples. Evaluation of quasi-periodic and periodic superlattices was performed by X-ray diffraction measurements. Five peaks were recorded for superlattices measurement of periodic structure by diffraction. The envelope of the diffraction pattern represents two separated peaks in investigation of Rudin Shapiro investigation. The results of the X-ay measurements showed low quality of the superlattices for both deposited structures which suggest the need for further optimization of the deposition process or the use of other materials of superlattices.