Ravipati, SrikanthSrikanthRavipatiShieh, JiannJiannShiehKo, Fu-HsiangFu-HsiangKoYu, Chen-ChiehChen-ChiehYuChen, Hsuen-LiHsuen-LiChenWu, Chia-TienChia-TienWuChen, Szu-HungSzu-HungChen2012-10-242018-06-282012-10-242018-06-282012http://ntur.lib.ntu.edu.tw//handle/246246/243588GaAs nanograss with diameters of less than 20 nm has been fabricated using a simple, one-step, maskless plasma etching-based approach. GaAs nanograss exhibits remarkable broadband antireflection properties, which arise from the graded refractive index between air and the GaAs substrate by the nanograss layer. Moreover, GaAs nanograss shows less sensitivity to transverse electric polarized light and transverse magnetic polarized light over a wide range of incident angles compared to the strong variation in a bare GaAs substrate. These effects show that sub-20 nm GaAs nanograss with lengths of approximately 200 nm has an enhanced absorption of 98-100% when the incident energy is larger than the GaAs bandgap (λ = 240-873 nm) and an enhanced absorption of 72-98% when the incident energy is less than the bandgap (λ = 873-2400 nm). Our simple, one-step, and maskless plasma etching method opens a promising approach for the direct implementation of broad omnidirectional antireflective surfaces on solar cells and various optoelectronic devices to improve device performance. © 2012 The Royal Society of Chemistry.en-US[SDGs]SDG7Energy gap; Light absorption; Light polarization; Optoelectronic devices; Plasma etching; Semiconducting gallium; Sensitivity analysis; Anti-reflection; Antireflective; Broadband and wide angle; Broadband antireflection; Device performance; Enhanced absorption; GaAs; GaAs substrates; Graded refractive indices; Incident angles; Incident energy; Mask less; Nanograss; Transverse electric polarized lights; Transverse-magnetic polarized lights; Gallium arsenide; absorption; arsenic; diameter; electronic equipment; gallium; nanotechnology; performance assessment; photovoltaic system; polarization; reflectivity; solar power; substratejournal article10.1039/c2ee21558fhttp://ntur.lib.ntu.edu.tw/bitstream/246246/243588/-1/28.pdf