Nur Irwany Ahmad
Thumbnail Image
Preferred name
Nur Irwany Ahmad
Official Name
Ahmad, Nur Irwany
Alternative Name
Ahmad, Nur Irwany
Main Affiliation
Scopus Author ID
57200991933

Research Output

Filters

1
2
Reset filters

Settings
Now showing 1 - 2 of 2
  • Publication
    Temperature-dependent properties of Cu-doped ZnTe thin films deposited on ultra-thin glass substrates via RF magnetron sputtering
    (Elsevier B.V., 2025-01)
    Nur Irwany Ahmad
    ;
    Ahmad Wafi Mahmood Zuhdi
    ;
    Camellia Doroody
    ;
    Yap Boon Kar
    ;
    Mohd Nazri Abd Rahman
    ;
    Kazi Sajedur Rahman
    ;
    Mohd Natashah Norizan
    ;
    Muhammad Najib Harif
    ;
    Tiong Sieh Kiong
    This study investigates the viability of Cu-doped ZnTe as a potential back surface field (BSF) layer on flexible CdTe thin-film solar cells, examining its structural, morphological, optical, and electrical properties. ZnTe, 5%, and 8% Cu-doped ZnTe were deposited on ultra-thin glass (UTG) substrates using the radio frequency (RF) magnetron sputtering approach at varying substrate temperatures from room temperature to 300 °C. The finding reveals that the surface morphology significantly changes as the substrate temperature increases. Besides, incorporating Cu into ZnTe resulted in a denser and rougher surface, likely due to material densification and accelerated grain growth at higher temperatures. X-ray diffraction (XRD) analysis indicated that the crystallite size of the ZnTe and Cu-doped ZnTe increased with higher temperatures. Optical spectroscopy results demonstrated an increase in the optical band gap of ZnTe with increasing substrate temperature, while Cu-doping introduced a significant variability in the bandgap, particularly at different doping levels. In terms of electrical properties, ZnTe thin films exhibited carrier concentrations around 1014 cm−3. Conversely, the introduction of 5% and 8% Cu into ZnTe increased carrier concentrations, ranging from 1017 to 1020 cm−3, respectively, depending on substrate temperature and the amount of Cu concentration. Introducing Cu in the ZnTe structure may modify the characteristics of ZnTe thin films, potentially influencing its suitability as a BSF layer in CdTe solar cells by affecting its structural, optical, and electrical properties.
  • Publication
    Copper doping effect in the back surface field layer of CdTe thin film solar cells
    ( 2024-02-01)
    Nur Irwany Ahmad
    ;
    Kiong T.S.
    ;
    Doroody C.
    ;
    Rahman K.S.
    ;
    Kar Y.B.
    ;
    Mohd Natashah Norizan
    ;
    Mohd Fairus Ahmad
    ;
    Harif M.N.
    ;
    Amin N.
    In this work, the Solar Cell Capacitance Simulator (SCAPS-1D) is employed to evaluate the characteristics of CdTe thin films with ZnTe as the Back Surface Field (BSF) layer and estimate the effective copper doping ratio at both the atomic scale and the device operational response perspective. The electrical characteristics of ZnTe, at varying levels of copper doping, were derived using density functional theory (DFT) by applying the generalized gradient approximation (GGA) and Hubbard U corrections (DFT+U). The performance of ZnTe with different Cu concentrations as a BSF layer was evaluated by analysing the values of four key parameters that are open circuit voltage (VOC), short circuit current density (JSC), fill factor (FF), and conversion efficiency (η). The results indicate that an increase in Cu concentration from 0% to 3%, 6%, 10%, and 12% resulted in a reduction of the energy band gap. Specifically, the energy band gap decreased from 2.24 eV to 2.10 eV, 1.98 eV, 1.92 eV, and 1.88 eV, respectively. Optimal Cu doping promotes the favourable shift in the valence band maxima (VBM) and formation of p + -ZnTe, lowering thermionic emission and improving carrier lifetime, which results in an improved ohmic contact, η = 18.73% for 10% of Cu content. Excessive doping in contrast degraded the overall device performance by forming an unmatched carrier band offset at the front interface with CdS, increasing the acceptor type defect and CdTe compensation rate. Overall, the findings suggest that incorporating a controlled level of Cu, which in this case is around 10%, promotes the efficiency and stability of the proposed CdTe device configuration to a certain extent.
      4  34