Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí hóa hoc quốc tế đề tài : Properties of nanocones formed on a surface of semiconductors by laser radiation: quantum confinement effect of electrons, phonons, and excitons | Medvid et al. Nanoscale Research Letters 2011 6 582 http content 6 1 582 o Nanoscale Research Letters a SpringerOpen Journal NANO REVIEW Open Access Properties of nanocones formed on a surface of semiconductors by laser radiation quantum confinement effect of electrons phonons and excitons Artur Medvid Pavels Onufrijevs and Alexander Mychko Abstract On the basis of the analysis of experimental results a two-stage mechanism of nanocones formation on the irradiated surface of semiconductors by Nd YAG laser is proposed for elementary semiconductors and solid solutions such as Si Ge SiGe and CdZnTe. Properties observed are explained in the frame of quantum confinement effect. The first stage of the mechanism is characterized by the formation of a thin strained top layer due to redistribution of point defects in temperature-gradient field induced by laser radiation. The second stage is characterized by mechanical plastic deformation of the stained top layer leading to arising of nanocones due to selective laser absorption of the top layer. The nanocones formed on the irradiated surface of semiconductors by Nd YAG laser possessing the properties of 1D graded bandgap have been found for Si Ge and SiGe as well however QD structure in CdTe was observed. The model is confirmed by blue shift of bands in photoluminescence spectrum red shift of longitudinal optical line in Raman back scattering spectrum of Ge crystal appearance of Ge phase in SiGe solid solution after irradiation by the laser at intensity 20 MW cm2 and non-monotonous dependence of Si crystal micro-hardness as function of the laser intensity. 1. Introduction Many experimental and theoretical investigations exist on heterostructures of self-assembled nanocones . Ge Si 1 InAs GaAs 2 . Usually nanocones are considered as quantum dots QDs -QD quantum system with a condition ratio diameter height of nanocones is equal 1. If solid angle a at top is 60 then the nanocone transforms into a .
