∼12% Efficiency improvement in a-Si thin-film solar cells using ALD grown 2-nm-thick ZnO nanoislands

2-nm-thick ZnO nanoislands have been grown using Atomic Layer Deposition (ALD) on the surface of n-i-p a-Si:H solar cells. With the nanoislands, an average improvement of 10.6% in short circuit current density (Jsc) and 12.05% in efficiency compared to the reference cell are achieved. Improved spectral response is obtained from ZnO nanoislands coated cell with an improvement of 4.2% and 5.25% in peak EQE and IQE respectively. The coated cell also minimizes reflection between 340-520 nm indicating light scattering ability of these nanoislands. Further analysis suggests that overall enhancement can be attributed to photon energy downshifting with a reduction in reflectivity.