Fabrication Of p-NiO/n-ZnO:Ga heterostructures for a rectifier diode and a UV photodetector via RF magnetron sputtering and spray pyrolysis synthesis

Institute Of Electronic Engineering And Nanotechnologies " ,Lidia Ghimpu,, Republic Of Moldova ,Victor Suman,Dumitru Ghitu" ,Dumitru Rusnac,Moldova State University ,Tamara Potlog,

doi:10.53081/mjps.2021.20-1.05

Institute Of Electronic Engineering And Nanotechnologies " , Lidia Ghimpu + Show 7 more

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https://doi.org/10.53081/mjps.2021.20-1.05

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Abstract

In this paper, a p–n thin film NiO/ZnO heterojunction for a rectifier diode and a UV photodetector is prepared and characterized. Nickel oxide (NiO) and gallium-doped zinc oxide (ZnO:Ga) thin films are grown by RF magnetron sputtering and spray pyrolysis techniques, respectively. The crystal structure of the thin films is studied by the X-ray diffraction (XRD) method. The transmittance and reflectance are studied by UV–VIS spectroscopy. The p–n electrical parameters are estimated from current–voltage characteristics. The effects of duration of thermal annealing at 450oC on the characteristics of the NiO/ZnO:Ga device are evaluated. The non-annealed diode shows the best rectification coefficient of 105 at ±1 V. The p–n photodetection capability is studied under UV illumination. At a reverse bias of –3 V under 365-nm UV illumination, the device shows a current intensity of ~6.2 × 10-12 A. The observed increase in the reverse current intensity by about two orders of magnitude under a UV lamp with a spectral irradiance of 10 W m-2 μ m-1 indicates a promising application in UV light detection.

Highlights

Metal oxide thin films have attracted much interest because of their electrical and optoelectronic characteristics and various applications
A UV detector based on lithium-doped Nickel oxide (NiO) and zinc oxide (ZnO) was reported by Ohta et al [12]
We describe the preparation and characterization of a heterojunction rectifier diode and a UV photodetector based on undoped NiO deposited by RF magnetron sputtering and Ga-doped ZnO grown by the spray pyrolysis technique

Summary

Introduction

Metal oxide thin films have attracted much interest because of their electrical and optoelectronic characteristics and various applications. Niobium oxide is inherently of the p-type because of the presence of native acceptor defects generated by nickel vacancies. Both materials have good band alignment [2, 3]. Zinc oxide and NiO have been extensively studied for use in electronic and optoelectronic devices, such as light emitting diodes, sensors, photodetectors, and thin film p–n junctions [2,3,4]. A variety of n-type metal oxide thin films has been studied for p–n junction diode or ultraviolet (UV) photodetector applications. Amorphous indium gallium zinc oxide (a-IGZO) has been widely studied because of its high mobility, good uniformity, low temperature process, and high optical transparency [6]. We describe the preparation and characterization of a heterojunction rectifier diode and a UV photodetector based on undoped NiO deposited by RF magnetron sputtering and Ga-doped ZnO grown by the spray pyrolysis technique

Experimental

Results and Discussion

Conclusions