Quyển tóm tắt (pdf) - Viện Vật lý

from abundant materials and compatible with economicmanufacturing processes, to commercial maturity.Although these devices are cheaper than their crystallinesilicon predecessors, they are usually also less efficient.In our research, we design nano-engineered materials thatwill improve energy conversion efficiencies while retainingthin-film manufacturing costs. We propose to boost thelight trapping within thin-film silicon solar cells byexploiting the adjustable aspect ratio of silicon nanowires.Batches of doped silicon nanowires are grown via plasmaenhanced VLS and coated in silicon so as to produce a PINjunction. The catalysts for the nanowire’s growth areproduced by reducing with a hydrogen plasma thetransparent conducting oxide layer on a standard PVindustry SnO2 substrate. By adapting the nanowires’length and thickness, we exert control over the cell’stexturing. This leads to promising light trapping effects,achieved in a single-pump down process.Working devices are reported with open circuit voltages ashigh as 0,80V. We present their I(V) characteristics andspectral response curves and discuss some of therecombination paths that may currently be limiting theperformance of these cells. We also explore furtheropportunities offered by silicon nanowires in terms ofdeveloping photovoltaics, including enhancing carriercollection and extending the absorption spectrum of thinfilm silicon solar cells.Người trình bày: Benedict O’Donnell33. Optical Transition Linewidths due toPiezoelectric Phonon Scattering in DopedSemiconductor SuperlatticesTrần Công Phong, Nguyễn Thị Lệ Thủy, VõThành Lâm, Lương Văn TùngUtilizing the optical transition formula derived by thestate-dependent projection method on the nonlinearresponse scheme, we obtain the optical transitionlinewidths for the electron system in dopedsemiconductor superlattices due to piezoelectric phononscattering. We find the dependence of the widths on thetemperature, the period of the superlattice, and thedoped concentration of the n-doping and p-doping layerin the respective layers. The present results for dopedsemiconductor superlattices are compared to those ofquantum wells.Người trình bày: Trần Công Phong34. Spectroscopy of an InAs/GaAs single quantumdot in a crystal photonic cavityNguyễn Hải SơnSemiconductor quantum dots are the artificialnanostructures where the electrons tri-dimensionconfinement produces a discreet energy spectrum as inthe atom systems. In consequence, a single quantum dotcan be considered a single photon emitter. Recenttechnology permits us to integrate a single quantum dotinto a high quality micro-cavity. This achievementThành phố Đồng Hới (03- 06/8/2009) Trang 41/ 102 Thành phố Đồng Hới (03- 06/8/2009) Trang 42/ 102