Physica B 670 (2023) 415400 Available online 9 October 2023 0921-4526/© 2023 Elsevier B.V. All rights reserved. Diode paremeters extraction and study of space charge limited current in (Ag, Au)/CoS 2 Schottky diodes S.M.T. Kazmi a , Z. Zahoor b , N.T. Yusra b , M.H. Bhatti a , M.F. Afsar a , F. Sher c , Haroon-ur Rashid b , M.A. Rafiq a, * a Condensed Matter Physics Laboratories, Department of Physics and Applied Mathematics, Pakistan Institute of Engineering and Applied Sciences (PIEAS), P. O. Nilore, Islamabad, 4650, Pakistan b Department of Electrical Engineering, Pakistan Institute of Engineering and Applied Sciences (PIEAS), P. O. Nilore, Islamabad, 4650, Pakistan c Department of Chemistry, SBA School of Science and Engineering, LUMS, Lahore, Pakistan A R T I C L E INFO Keywords: Cobalt sulfide Schottky diode Space charge limited current Richardson’s coefficient Electron transport Solid state reaction ABSTRACT We investigated the electron transport properties of cobalt sulphide Schottky diodes with Au and Ag metal contacts. Pure CoS 2 nanoplates were synthesized using solid state reaction method. From temperature dependent IV characterstics diode parameters including ideality factor, barrier height and Richardson cofficient were calculated for Au/CoS 2 and Ag/CoS 2 diodes. The value of barrier height increased with increasing temperature for both devices, however Ideality factor showed different trend. The values of modified Richardson coefficient by assuming the Gaussian distribution of the barrier heights turns out to be 244.20 Acm  2 K  2 and 348.20 Acm  2 K  2 for Au/CoS 2 and Ag/CoS 2 diodes respectively. At high voltages we observed Space Charge Limited Current (SCLC) with an exponential trap distribution in Au/CoS 2 diode. The density of the traps and characteristic temperature associated with these traps were determine to be 2.47 × 10 14 cm  3 and 141 K, respectively. 1. Introduction Cobalt sulfide is an important semiconductor material and its stoi- chiometric complexity leads in a number of phases like CoS, CoS 2 , Co 3 S 4 , etc. With its distinctive electrical, magnetic, and catalytic properties cobalt sulfide is a promising candidate in various applications, including supercapacitors [1,2], solar selective coatings [3], catalysis for hydrogen generation [4,5], and field effect transistors [6,7]. In the po- tential applications of cobalt sulfide in various devices, a comprehensive understanding of its electrical properties and transport mechanism are important. Especially in semiconductor devices metal-semiconductor (MS) contact named as Schottky diode is important aspect. Today, the Schottky diodes are used as microwave diodes, rectifiers, UV detectors, photo sensors, switching diodes and solar cells [8–12]. Due to the technological importance of Schottky diodes, investigation of diode parameters such as Richardson coefficient, ideality factor, potential barrier height, and a full understanding of carrier’s conduction mecha- nisms is of great importance. The Schottky diode parameters can be extracted from the investigation of the current-voltage (IV) characteristics, based on thermionic emission diffusion (TE) theory [13]. Only study of IV char- acteristics at room temperature does not provide enough information regarding the current conduction mechanisms and barriers at the metal semiconductor interface. Temperature-dependent IV measurements provide considerable information regarding diode parameters and cur- rent conduction mechanisms [14,15]. Since the Richardson constant is used to calculate the barrier height, it is necessary to know its precise value or its value in temperature range in which barrier height is being calculated. However, the large disparity between the expected and estimated Richardson coefficient using classical TE model could be due to potential fluctuations and lateral inhomogeneity of the barrier at an interface. More accurate value of Richardson coefficients can be calcu- lated by assuming the Gaussian distribution of the potential barrier heights [13,16,17]. Different current conduction mechanisms can be distinguished on the bases of power law (I ~ V m ). The lnI-InV plot can have different regions with different slopes (m), these regions corre- spond to different current conduction mechanisms [18,19]. A region with slope ~1, especially at low voltages corresponds to ohmic region. * Corresponding author. E-mail address: aftab@cantab.net (M.A. Rafiq). Contents lists available at ScienceDirect Physica B: Condensed Matter journal homepage: www.elsevier.com/locate/physb https://doi.org/10.1016/j.physb.2023.415400 Received 20 September 2023; Received in revised form 5 October 2023; Accepted 7 October 2023