TiO2/CuO/Cu2O Photovoltaic Nanostructures Prepared by DC Reactive Magnetron Sputtering

Abstract

In this study, titanium dioxide/copper oxide thin-film solar cells were prepared using the reactive direct-current magnetron sputtering technique. The influence of the deposition time of the top Cu contact layer on the structural and electrical properties of photovoltaic devices was analyzed. The structural and morphological characterization of the TiO2/CuO/Cu2O solar cells was fully studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), and current–voltage (I-V) characteristics. Additionally, using van der Pauw sample geometries, the electrical properties of the titanium dioxide and copper oxide layers were investigated. From the XRD study, solar cells were observed in cubic (Cu2O), monoclinic (CuO), and Ti3O5 phases. In addition, the crystallite size and dislocation density for copper oxide layers were calculated. Basic morphological parameters (thickness, mechanism of growth, and composition of elements) were analyzed via scanning electron microscopy. The thicknesses of the titanium dioxide and copper oxide layers were in the range of 43–55 nm and 806–1223 nm, respectively. Furthermore, the mechanism of growth and the basic composition of the elements of layers were analyzed. The I-V characteristic curve confirms the photovoltaic behavior of two titanium dioxide/copper oxide thin-film structures. The values of short-circuit current density (Jsc) and open-circuit voltage (Voc) of the solar cells were: 4.0 ± 0.8 µA/cm2, 16.0 ± 4.8 mV and 0.43 ± 0.61 µA/cm2, 0.54 ± 0.31 mV, respectively. In addition, the authors presented the values of Isc, Pmax, FF, and Rsh. Finally, the resistivity, carrier concentration, and mobility are reported for selected layers with values reflecting the current literature.

Formation and Characterization of Stable TiO2/CuxO-Based Solar Cells

“…Diffusion processes regulate the homogeneity of the film in the lateral direction. Transport from the vapor phase (layer growth) controls the homogeneity of the film in the normal direction [ 66 ]. The formation of a uniform film structure can occur only when, in the process of growth, atoms can freely pass between the layers of the film.…”

“…Among many heterojunction solar cells being considered in literature (see e.g., [ 57 , 58 , 59 , 60 , 61 , 62 , 63 ]), our group deals with TiO 2 /Cu x O and we already published several papers with investigations of TiO 2 and Cu x O cells fabricated with the direct current magnetron sputtering (DC-MS) with different process conditions [ 38 , 40 , 64 , 65 , 66 ]. In [ 64 ] TiO 2 , Cu 2 O, as well as TiO 2 /Cu 2 O, structures were investigated, with the wide variety of measurements carried out: morphology, cross-section, topography, roughness, and transmission spectra of the films.…”

“…In 2021, again by applying different parameters, such as substrate temperature, oxygen and argon flow rates, as well as time deposition for the TiO 2 /Cu 2 O/CuO/Cu 2 O cell, the authors obtained the efficiency of 0.9%, which is the best result so far [ 38 ]. In [ 66 ], the authors investigated TiO 2 /CuO/Cu 2 O solar cells with the following measurements: X-ray diffraction, scanning electron microscopy, and current–voltage characteristics. The main goal was to check how the deposition times of the top contact point of Cu and the TiO 2 layer influence the structural and electrical properties of solar cells being investigated.…”

Optimizing the structure and optoelectronic properties of cuprite thin films via a plasma focus device as a solar cell absorber layer

“…7 In this milieu, cuprous oxide (Cu 2 O) emerges with pivotal attributes, rendering it a prospective candidate for absorption layers in solar cell configurations. 8 The material has garnered substantial attention, attributed to its exemplary optical and electrical properties, 9 prolific availability, 10 and economic viability. 11 A wealth of research has delved into exploring the potential of Cu 2 O in diverse applications, such as gas sensing and exemplifying notable photocatalytic performance.…”

Optical Properties of ITO/Glass Substrates Modified by Silver Nanoparticles for PV Applications

“…The authors manufactured thin-film solar cells based on layers of copper oxide and titanium dioxide or zinc oxide by reactive DC magnetron sputtering with low efficiency (maximum ~0.9%) [2,8,9]. This construction is not feasible for large-scale fabrication.…”