Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí hóa hoc quốc tế đề tài : Enhanced photo-sensitivity through an increased light-trapping on Si by surface nano-structuring using MWCNT etch mask | Hwang et al. Nanoscale Research Letters 2011 6 573 http content 6 1 573 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Enhanced photo-sensitivity through an increased light-trapping on Si by surface nano-structuring using MWCNT etch mask Min-Young Hwang 1 Hyungsuk Kim1 Eun-Soo Kim1 Jihoon Lee1 2 and Sang-Mo Koo1 Abstract We demonstrate an enhanced photo-sensitivity PS through an increased light-trapping using surface nanostructuring technique by inductively coupled plasma ICP etching on multi-walled carbon nanotube MWCNT etch masked Si with hexamethyl-disilazane HMDS dispersion. In order for a systematic comparison four samples are prepared respectively by conventional photolithography and ICP etching using MWCNT as a etch mask. MWCNT-etched Si with HMDS dispersion shows the highest RMS roughness and the lowest reflectance of the four. Two test device structures are fabricated with active regions of bare-Si as a reference and MWCNT etch masked Si with HMDS dispersion. The increased light-trapping was most significant at mid-UV somewhat less at visible and less noticeable at infrared. With an ICP-etched Si using CNT HMDS dispersion PS is very sharply increased. This result can lead to applications in optoelectronics where the enhancement in light-trapping is important. Introduction Light-trapping in other word optical absorption in such device applications as photovoltaics light-emitting diodes light sensors photo-diodes and transistors plays an important role in their device functionality and in order to suppress reflection losses and increase conversion efficiency 1-10 . In general approximately 30-40 of photons are reflected when incident on planar wafers. Theoretically through an ideal light-trapping the length of optical path in a material with a refractive index of n can be enhanced by a factor of 4n2 11 and thus the amount of photons that can be absorbed in a material can be significantly enhanced. .
