Impact of Thickness, Doping and Resistance Losses on Photovoltaic Performance in a-Si:H p-i-n Solar Cells

Öz

In this study, the performance of p-i-n solar cells based on hydrogenated amorphous silicon (a-Si:H) was comprehensively investigated using the SCAPS-1D numerical simulation tool. In the cell structure with a front contact / p-aSi:H / i-aSi:H / n-aSi:H / back contact architecture, the effects of layer thicknesses, p- and n-type doping concentrations (NA and ND), and series and shunt resistances (Rs and Rsh) on the open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), and power conversion efficiency (η) were investigated. The simulations were performed at a constant temperature of 300 K and under the AM1.5G solar spectrum. The results obtained demonstrate that the thickness of the intrinsic a-Si:H layer directly determines the photogeneration mechanism, and that increasing the thickness from 200 nm to 600 nm significantly enhances light absorption and carrier generation. This increase resulted in a rise in short-circuit current density to approximately 19 mA.cm⁻²; thanks to only a limited decrease in open-circuit voltage, the total power conversion efficiency reached 9.6%. Selecting a doping concentration of 1×10¹⁹ cm⁻³ in p- and n-type a-Si:H layers enhanced the built-in electric field, improving carrier separation and transport; this provided significant gains, particularly in the Voc and FF parameters. Furthermore, it was revealed that the increase in series resistance limits efficiency through the fill factor, while low shunt resistance causes significant losses in Voc and FF due to leakage currents. The interaction between geometric and doping parameters in a-Si:H p-i-n solar cells was explained in detail, and optimized device parameters were determined.

Anahtar Kelimeler

• Thin-film solar cells
• photovoltaic performance
• Amorphous silicon (a-Si:H)
• layer optimization

a-Si:H p-i-n Güneş Pillerinde Kalınlık, Katkılama ve Direnç Kayıplarının Fotovoltaik Performansa Etkisi

Öz

Bu çalışmada, hidrojenlenmiş amorf silikon (a-Si:H) tabanlı p-i-n güneş hücrelerinin performansı, SCAPS-1D sayısal benzetim aracı kullanılarak kapsamlı biçimde incelenmiştir. Ön kontak / p-aSi:H / i-aSi:H / n-aSi:H / arka kontak mimarisine sahip hücre yapısında, katman kalınlıkları, p- ve n-tipi katkılama yoğunlukları (N_A ve N_D) ile seri ve şönt dirençlerin (R_s ve R_sh) açık devre gerilimi (Voc), kısa devre akım yoğunluğu (Jsc), doluluk faktörü (FF) ve güç dönüşüm verimi (η) üzerindeki etkileri değerlendirilmiştir. Simülasyonlar, 300 K sabit sıcaklık ve AM1.5G güneş spektrumu altında gerçekleştirilmiştir. Elde edilen sonuçlar, intrinsik a-Si:H tabakasının kalınlığının fotogenerasyon mekanizmasını doğrudan belirlediğini ve kalınlığın 200 nm’den 600 nm’ye çıkarılmasıyla ışık soğurumu ve taşıyıcı üretiminin önemli ölçüde arttığını göstermektedir. Bu artış, kısa devre akım yoğunluğunun yaklaşık 19 mA.cm⁻² seviyesine yükselmesini sağlamış; açık devre geriliminde yalnızca sınırlı bir azalma gözlenmesi sayesinde toplam güç dönüşüm verimi %9.6’ya ulaşmıştır. p- ve n-tipi a-Si:H tabakalarda katkılama yoğunluğunun 1×10¹⁹ cm⁻³ seviyesinde seçilmesi, yerleşik elektrik alanı güçlendirerek taşıyıcı ayrışmasını ve taşınımını iyileştirmiş; özellikle Voc ve FF parametrelerinde belirgin kazanımlar sağlamıştır. Buna ek olarak, seri direncin artmasının doluluk faktörü üzerinden verimliliği sınırladığı, düşük şönt direncin ise kaçak akımlar nedeniyle Voc ve FF’de ciddi kayıplara yol açtığı ortaya konmuştur. a-Si:H p-i-n güneş hücrelerinde geometrik ve katkısal parametreler arasındaki karşılıklı etkileşim ayrıntılı biçimde açıklanarak, optimize edilmiş cihaz parametreleri belirlenmiştir.

Anahtar Kelimeler

• İnce film güneş pilleri
• fotovoltaik performans
• Amorf silikon (a-Si:H)
• katman optimizasyonu

Kaynakça

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