Sains Malaysiana 51(5)(2022): 1567-1576 http://doi.org/10.17576/jsm-2022-5105-24 Carrier Density and Thickness Optimization of In x Ga 1-x N Layer by Scaps-1D Simulation for High Efficiency III-V Solar Cell (Pengoptimuman Ketumpatan Pembawa dan Ketebalan Lapisan In x Ga 1-x N dengan menggunakan Simulasi Scaps-1D untuk Kecekapan Tinggi Sel Suria III-V) HABIB ULLAH MANZOOR 1,2 , TAN AIK KWAN 1 , NG SHA SHIONG 1,* & ZAINURIAH HASSAN 1 1 Institute of Nano Optoelectronics Research and Technology (INOR), Universiti Sains Malaysia, 11800 USM, Penang, Malaysia 2 University of Engineering and Technology, Lahore-FSD Campus, Pakistan Received: 15 July 2021/Accepted: 29 September 2021 ABSTRACT In this study, the indium gallium nitride (In x Ga 1-x N) p-n junction solar cells were optimized to achieve the highest conversion efficiency. The In x Ga 1-x N p-n junction solar cells with the whole indium mole fraction (0 ≤ x ≤ 1) were simulated using SCAPS-1D software. Optimization of the p- and n-In x Ga 1-x N layer’s thickness and carrier density were also carried out. The thickness and carrier density of each layer was varied from 0.01 to 1.50 μm and 10 15 to 10 20 cm -3 . The simulation results showed that the highest conversion efficiency of 23.11% was achieved with x = 0.6. The thickness (carrier density) of the p- and n-layers for this In 0.6 Ga 0.4 N p-n junction solar cell are 0.01 (10 20 ) and 1.50 μm (10 19 cm -3 ), respectively. Simulation results also showed that the conversion efficiency is more sensitive to the variations of layer’s thickness and carrier density of the top p-In x Ga 1-x N layer than the bottom n-In x Ga 1-x N layer. Besides that, the results also demonstrated that thinner p-In x Ga 1-x N layer with higher carrier density offers better conversion efficiency. Keywords: Photovoltaics; semiconducting indium compounds; solar energy; thin films solar cell; III-V nitride ABSTRAK Dalam kajian ini, sel suria indium galium nitrida (In x Ga 1-x N) bersimpang p-n telah dioptimumkan untuk mencapai kecekapan penukaran yang tertinggi. Sel suria In x Ga 1-x N bersimpang p-n dengan keseluruhan pecahan mole indium (0 ≤ x ≤ 1) telah disimulasi dengan menggunakan perisian SCAPS-1D. Pengoptimuman untuk ketebalan dan ketumpatan pembawa bagi lapisan p- dan n-InGaN juga telah dijalankan. Ketebalan dan ketumpatan pembawa bagi setiap lapisan telah diubah daripada 0.01 hingga 1.50 µm dan 10 15 hingga 10 20 cm -3 . Keputusan simulasi menunjukkan bahawa kecekapan penukaran tertinggi sebanyak 23.11% telah dicapai dengan x = 0.6. Ketebalan (ketumpatan pembawa) bagi lapisan p- dan n- untuk sel suria In 0.6 Ga 0.4 N adalah 0.01 (10 20 ) dan 1.50 µm (10 19 cm -3 ), masing-masing. Keputusan simulasi juga menunjukkan bahawa kecekapan penukaran adalah lebih sensitif terhadap perubahan ketebalan dan ketumpatan pembawa bagi lapisan p-In x Ga 1-x N atas berbanding dengan lapisan n-In x Ga 1-x N bawah. Selain itu, keputusan simulasi juga menunjukkan bahawa lapisan p-In x Ga 1-x N yang lebih nipis bersama dengan ketumpatan pembawa yang lebih tinggi memberi kecekapan penukaran yang lebih tinggi. Kata kunci: Fotovolta; sebatian semikonduktor indium; sel suria filem nipis; tenaga suria; III-V nitrida I NTRODUCTION III-V nitride semiconductors are widely used in t he past few decades in optoelectronic devices. Wide direct bandgap indium gallium nitride (In x Ga 1-x N) ternary alloys are considered pivotal materials in photovoltaic applications because their bandgap energy (E g ) can be engineered to fit the entire solar spectrum (Zhang et al. 2019). Generally, their E g can be varied from 3.42 (GaN)