Combined micro- and nano-scale surface textures for enhanced near-infrared light harvesting in silicon photovoltaics.
As silicon photovoltaics evolve towards thin-wafer technologies, efficient optical absorption for the near-infrared wavelengths has become particularly challenging. In this work, we present a solution that employs combined micro- and nano-scale surface textures to increase light harvesting in the near-infrared for crystalline silicon photovoltaics, and discuss the associated antireflection and scattering mechanisms. The surface textures are achieved by uniformly depositing a layer of indium-tin-oxide nanowhiskers on micro-grooved silicon substrates using electron-beam evaporation. The nanowhiskers facilitate optical transmission in the near-infrared by functioning as impedance matching layers with effective refractive indices gradually varying from 1 to 1.3. Materials with such unique refractive index characteristics are not readily available in nature. As a result, the solar cell with combined textures achieves over 90% external quantum efficiencies for a broad wavelength range of 460-980 nm, which is crucial to the development of advanced thin-substrate silicon solar cells.
Department of Photonics, National Chiao-Tung University, Hsinchu, Taiwan, Republic of China.
Chia-Hua
CH
Chang
Peichen
P
Yu
Min-Hsiang
MH
Hsu
Ping-Cheng
PC
Tseng
Wei-Lun
WL
Chang
Wen-Ching
WC
Sun
Wei-Chih
WC
Hsu
Shih-Hsin
SH
Hsu
Yia-Chung
YC
Chang
D003460:Crystallization / Q000379:methods; D011211:Electric Power Supplies; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007259:Infrared Rays; D008027:Light; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry* / Q000528:radiation effects*; D036103:Nanotechnology / Q000295:instrumentation*; D012825:Silicon / Q000737:chemistry*; D012993:Solar Energy; D013499:Surface Properties
D012825:Silicon