Ahmad Zaidi Abdullah
Thumbnail Image
Preferred name
Ahmad Zaidi Abdullah
Official Name
Ahmad Zaidi, Abdullah
Alternative Name
Bin Abdullah, Ahmad Zaidi Bin
Abdullah, Ahmad Zaidi Bin
Abdullah, Ahmad Zaidi
Abdullah, A. Z.
Main Affiliation
Scopus Author ID
56878313200
Researcher ID
W-3280-2019

Research Output

Filters

3
3
Reset filters

Settings
Now showing 1 - 3 of 3
Thumbnail Image
Publication

First Principles Enhanced Electronic Band Structure of Back Contact in CdTe Solar Cells using DFT+U Method

2023-01-01 , Ahmad N.I. , Nurhafiza Azizan , Kar Y.B. , Doroody C. , Syahrun Nizam Md Arshad @ Hashim , Ahmad Zaidi Abdullah , Jamal A.

Cadmium telluride (CdTe) superstrate solar cells have captivated the industry with their remarkable cost-effectiveness. However, optimizing the composition and optoelectrical properties of optimal back surface field (BSF) which can act as a lattice matching interface between the back contact and absorber layer remains a key challenge due to the work function disparity of p-CdTe with metal contacts. In this study, the influence of the Hubbard U parameter on the calculated electronic properties of ZnTe as an optimal BSF compound is presented using the density functional theory (DFT) technique. The Hubbard U value progressively increased from 1 to 4.2 to analyze its influence on the band diagram and Total Density of States (TDOS) in a full comparison of DFT and DFT+U approaches. As the value of Hubbard U increased, the band gap energy exhibited a corresponding increase from 1.20 eV to 2.24 eV, respectively. In comparison, the DFT+U approach with a value of 4.2 exhibited superior accuracy in predicting the band gap of ZnTe, yielding a value of 2.24 eV that closely approximated experimental measurements. This finding reinforces the relevance of employing Hubbard U to achieve more accurate and reliable band gap values for any material doping.

View
Thumbnail Image
Publication

A Contemporary Review of High Voltage Partial Discharge Detection and Recognition Techniques

2023-07-01 , Bohari Z.H. , Muzamir Isa , Faizah Abu Bakar , Ahmad Zaidi Abdullah , Ayob Nazmy Nanyan , Nasir M.N.M. , Sulaima M.F. , Ahmad E.Z.

This review article provides a summary of the most advanced approaches and advancements in the detection and recognition of high voltage partial discharge (PD). It discusses numerous detecting technologies, such as electrical, acoustic, and optical approaches, as well as their merits and disadvantages. It also discusses current developments in signal processing and pattern recognition algorithms used for PD detection and classification. Lastly, the study covers the challenges and limitations in high voltage PD detection and identification studies, as well as potential future solutions.

View
Thumbnail Image
Publication

The magnetic flux density of various geometries of Rogowski Coil for overvoltage measurements

2020-01-01 , Ayob Nazmy Nanyan , Mohamad Nur Khairul Hafizi Rohani , Muzamir Isa , Afifah Shuhada Rosmi , Ahmad Zaidi Abdullah , Baharuddin Ismail , Haziah Abdul Hamid

Overvoltage phenomenon is the common problem that always occurs in the power system and can cause the electrical system network breakdown, and in some cases, it may explode. The frequent overvoltage also can affect and degrade the lifespan of the electrical power system components and network. Thus, the overvoltage sensor is needed to overcome this problem matter. The Rogowski coil (RC) is one of an inductive coil group, and it is suitable for measuring the alternating current (AC) and transient currents or overvoltage. This paper demonstrated the effect of RC magnetic flux density, B with difference cross-section, geometries sizing and the number of turns by using Finite Element Method (FEM). Commonly, there are three types of RC widely used; rectangular, circular and oval. Each of these cross-sections has different characteristics in term of performance. The results have shown that the rectangular cross-section is better than oval and circular cross-section based on the number of magnetic flux density.

View