Production of Al/P-Si/ZnO:B4C /al photodiodes by sol-gel spin-coating method, determination of photoresponse and electrical properties properties

In this study, Al/P-Si/ZnO:B4C/Al photodiodes were produced using the sol-gel spin-coating method, and their photoresponse and electrical properties were analyzed in detail. The aim of the study was to enhance the performance and optimize the light sensitivity of the photodiodes by adding various ratios of boron carbide (B4C) to ZnO. Structural and morphological characterizations were performed using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis. The current-voltage (I-V) characteristics of the photodiodes were tested under dark conditions and at different light intensities ranging from 20 to 100 mW/cm² using a solar simulator. The experimental results showed a significant increase in reverse current with increasing B4C content. It was determined that the photodiodes are highly sensitive to light. At 100 mW/cm² light intensity, the photocurrents were measured as 56 × 10⁻⁴ A, 16.4 × 10⁻⁵ A, 6.97 × 10⁻⁵ A, 3.43 × 10⁻⁵ A, and 2.67 × 10⁻⁵ A for 0%, 1%, 3%, 5%, and 10% B4C ratios, respectively. Sudden increases in photocurrent were observed when the photodiodes were exposed to light, and upon termination of illumination, the photocurrents rapidly returned to their initial levels, demonstrating reversible switching behavior. It was found that B4C addition reduced the light sensitivity of the photodiodes under reverse bias by limiting the separation of charge carriers but provided more stable current values under forward bias. The results indicate that Al/P-Si/ZnO:B4C/Al composite photodiodes offer promising alternatives in terms of photoconductive and photovoltaic performance, contributing to the development of high-efficiency solutions for solar energy conversion systems and optoelectronic applications.