Seong Hyun Lee

Antireflection Properties of Al2O3 and Al x Ti1 − x O y Films on ZnO:Ga Coated Si Wafer for Thin-Film Solar Cell

The antireflection (AR) properties of Al 2 O 3 and Al x Ti 1―x O y films were investigated for the application of an AR coating of thin-film solar cells. Their optical transmittance was measured to exceed 85% over the entire visible and near-IR spectrum. The AR layers of these films coated on transparent conductive oxide (TCO)/Si exhibited 18% lower reflection than an uncoated TCO/Si at wavelengths from 400 to 900 nm. Furthermore, the thicknesses of the AR layers and TCO were demonstrated to influence the amount and shape of reflectivity in the reflection curves for the AR/TCO/Si structure.

Ultraviolet responses of a heterojunction Si quantum dot solar cell.

We investigated the ultraviolet (UV) responses of a heterojunction Si quantum dot (QD) solar cell consisting of p-type Si-QDs fabricated on a n-type crystalline Si (p-Si-QD/n-c-Si HJSC). The UV responses were compared with a conventional n-type crystalline Si solar cell (n-c-Si SC). The external and internal quantum efficiency results of the p-Si-QD/n-c-Si HJSC exhibited a clear enhancement in the UV responses (300-400 nm), which was not observed in the n-c-Si SC. Based on the results of the cell reflectance and bias-dependent responses, we expect that almost all UV responses occur in the p-Si-QD layer, and the generated carriers can be transported via the Si-QD layer due to the formation of a sufficient electric filed. As a result, a high power conversion efficiency of 14.5% was achieved from the p-Si-QD/n-c-Si HJSC. By reducing the thickness of the n-Si substrate from 650 μm to 300 μm, more enhanced power conversion efficiency of 14.8% was obtained which is the highest value among the reported Si-QD based solar cells to date.