Structural, optical, and electrical characterizations of Cr-doped CuO thin films

Silan Baturay,Cihat Ozaydın,Ilhan Candan

doi:10.1007/s10854-022-07918-2

Silan Baturay, Cihat Ozaydın + Show 1 more

Open Access

https://doi.org/10.1007/s10854-022-07918-2

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Abstract

The polycrystalline copper oxide (CuO) thin films have been produced using the method of spin coating on the soda–lime glass (SLG) as well as the substrate of p-type Si (1 0 0) wafers at 500 °C in furnace. The obtained undoped and Cr-doped thin films of CuO have been comprehensively characterized via X-ray diffraction (XRD), ultraviolet–vis (UV–Vis) spectroscopy, the current–voltage (I–V), and capacitance–voltage (C–V) characteristics for providing information on quality of the crystalline nature, change in energy band gap and electrical properties, respectively. Structural analysis results obtained from XRD data demonstrate that CuO films in conjunction with Cr doping indicated that all thin films have monoclinic polycrystalline nature, with two main peaks of (− 111) and (111) with dhkl of about 2.52 and 2.32 Å, respectively. The transmittance and energy band gap values of undoped and Cr-doped thin films of CuO ranging in varying concentration ratio have been determined in the wavelength region of 300–1100 nm. The highest value has been found to be around 33% related to 3% Cr doping in the visible range. UV–Vis spectrum analysis results indicate that both transmittance value and energy band gap value of the CuO films are changed with the increase in Cr doping ratio in CuO solution at room temperature. The band gap energy was determined to be between 1.67 and 2.03 eV with the increase in Cr concentration. The I–V and C–V characteristics of Cr:CuO/p-Si diodes were associated with the CuO/p-Si diodes. Although the best rectification ratio (RR) is seen in the 1% Cr-doped diode (RR = 2.33 × 103 for ± 1 V), other diodes also have significant rectification behavior. It is seen that doping of Cr had a significant change on the obtained devices’ performance. Thus, the Cr:CuO/p-Si diodes generated by 1% Cr doping using spin coating method had the highest light sensitivity compared with those of the other diodes.

Highlights

The metal oxide nanostructures’ extraordinary properties and structural difference started wide-ranging research focus in various nanoscale fields including electronics, catalysis, optics, optoelectronics, and biosensors [1,2,3,4]
Cr doped cupric oxide (CuO) thin films were grown on soda lime glass (SLG) substrate and CuO/p-Si and Cr:CuO/p-Si structures were produced by depositing thin films on p-type Si wafers using method of spin coating and annealed at 500 °C for 1h in air condition
The obtained thin film’s X-ray diffraction (XRD) parameters including crystallite size, dislocation density and strain is slightly changed with increasing Cr concentration

Summary

Introduction

The metal oxide nanostructures’ extraordinary properties and structural difference started wide-ranging research focus in various nanoscale fields including electronics, catalysis, optics, optoelectronics, and biosensors [1,2,3,4]. Metalsemiconductor (MS) and metal-interlayer-semiconductor (MIS) type Schottky diodes’ electrical properties started considerable interest in experimental studies owing to metal and semiconductor interlayer’s different optical and electrical properties [24,25] Since these devices’ performance and reliability is based on the interlayer formation, these devices effect parameters of the device including the barrier height, interface-state density, series resistance as well as ideality factor. Samarasekara et al fabricated thin films of CuO using sol-gel spin coating tehnique and investigated Zn2+ doped CuO thin films’ electrical properties. Shaban et al employed spin-coating technique to investigate phase mixed with Cu2O/CuO structural, optical and gas sensing properties and they found that the sensitivity of 6 % Cr and 3 % S doping of Cu2O/CuO thin films significantly improved from 46 to 99.8 % towards flow rate of Co2 increased from 30 to 150 sccm [33]. We have investigated the diodes’ electrical properties to analyze the concentration effect on diode parameters of Cr:CuO/p-Si diodes by employing measurements of current–voltage (I–V) and capacitance– voltage (C–V) in the dark and light (100 mW/cm2)

Experimental

Structural properties

Optical Properties

Findings

Conclusion