Temperature and tellurium (Te) dependence of electrical characterization and surface properties for a chalcopyrite structured schottky barrier diode

• Published in: Journal of alloys and compounds Vol. 585; pp. 178 - 184
• Main Authors: Fiat, Songül, Bacaksiz, Emin, Kompitsas, Michael, Çankaya, Güven
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 05.02.2014; Elsevier
• Subjects: AFM; Alloys; Barriers; CIGSeTe; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Diodes; Electrical properties; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Morphology; Physics; Schottky barrier diodes; Semiconductors; Surface double layers, schottky barriers, and work functions; Surface properties; Volt-ampere characteristics; AFM; Schottky barrier diodes; Electrical properties; CIGSeTe; Selenides tellurides; Schottky barriers; Gaussian distribution; Acoustic surface waves; Metal-semiconductor contacts; Chalcopyrite; Thermionic emission; Surface properties; Chemical composition; Barrier height; Microstructure; IV characteristic
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2013.09.123

Two different compositions of CuIn0.7Ga0.3(Se(1−x)Tex)2 (x=0. 0 and 0.6) have been synthesized in quartz ampoules coated with carbon. The prepared compounds of CuIn0.7Ga0.3(Se(1−x)Tex)2 for x=0.0 and 0.6 evaporated on Mo coated glass substrates at 150 °C with electron-beam evaporation system. For schottky contact fabrication Al contact (∼500nm) was evaporated on Mo/CuIn0.7Ga0.3(Se(1−x)Tex)2 structure. Then electrical properties were characterized with current–voltage (I–V) and capacitance–voltage (C–V) measurements in 150–300K temperature range. Also AFM images were obtained for Mo/p-CuIn0.7Ga0.3(Se(1−x)Tex)2 structures for x=0.0 and 0.6 amounts. [Display omitted] •CuIn0.7Ga0.3(Se(1−x)Tex)2 compound ingots were prepared from mixtures of pure Cu, In, Ga, Se and Te elements and front contact Al and ohmic contact Mo was prepared by sintering evaporated for different x amounts (0.0 and 0.6) of Te. Se+Te effect in such diodes originated chalcopyrites compounds is a novel search topic.•Some diode parameters such as; ideality factor, barrier height, Richardson constants, flat band barrier heights and temperature coefficients were calculated as a function of temperature in a range of 150–300K from the I–V measurements and plotted as a function of temperature and Te doping amount.•We report that electrical properties of these two diodes can be defined on the basis of the Thermionic emission (TE) theory with the Gaussian distribution (GD) of the SBH being related to inhomogeneities at the M/S interface. Electrical properties were found to be strongly dependent to temperature and Te amount.•Also surface properties showed us that there became a better morphology in Te rich samples with higher pellets on surface with Te. Al/p-CuIn0.7Ga0.3(Se(1−x)Tex)2/Mo Schottky barrier diodes (SBD) have been investigated as electrical and morphological. Electrical characterization and surface maps of the prepared CuIn0.7Ga0.3(Se(1−x)Tex)2 (briefly, CIGSeTe) compounds with two different compositions for x=0.0 and 0.6 were examined in 150–300K range. CIGSeTe films were grown on Mo back contact. Some electrical parameters such as, ideality factors, n; zero-bias barrier heights, Φbo and Richardson constants were calculated from the current–voltage (I–V) measurements and plotted as a function of temperature. These results verify that electrical properties of these two diodes can be defined on the basis of the Thermionic emission (TE) theory with the Gaussian distribution (GD) of the Schottky barrier height (SBH) being related to inhomogeneities at the metal/semiconductor (MS) interface. On the other hand, we saw a better morphology in Te rich samples. Rms (root mean square) values increased from 8.50nm to 9.80nm with higher pellets on surface with Te.