Abstract
A-Si:H p-i-n photodiodes with scintillators to detect high energy particles including X-ray photons have been studied more than decade. And they were practically integrated with radiography machine as the X-ray sensor. In order to improve diodes' sensitivity and efficiency, we must improve the optical absorption efficiency of a-Si:H p-i-n diodes. So we engaged in improve the efficiency of single p-i-n and tandem cell structure. In our experiments, the growth conditions to prepare the p, i, n layers of solar cells by using ECRCVD was found. We design and fabricate the solar cells include single pin and tandem cell structures. From the results of I-V measurements, the efficiency of single pin structures were 2.85%, 2.145%, 2.88%, and the efficiency of a-Si/ □c-Si tandem cell was 3.45%. The efficiency of tandem cell structure was higher than single pin structure. So, the tandem cell structure can be applied for medical imaging system in the future.