All authors read and approved the final manuscript.”
“Review Introduction Semiconductor nanostructures are the most investigated object in solid state physics due to their promising application in microelectronics and optoelectronics. Today we have some well-developed methods for the formation of nanostructures: MBE , CVD , ion
implantation , and laser ablation . The above-mentioned methods need subsequent thermal annealing of the structures in a furnace. Nanostructure growths by these methods need a lot of time and a high-vacuum or a special environment, for example, inert Ar gas. As a result, nanocrystals grow with uncontrollable parameters, broad size distribution, and chaotically, MDV3100 concentration the selleck so-called self-assembly. Therefore, one of the important tasks for nanoelectronic and optoelectronic growth is the elaboration of new methods for the formation of nanostructures in semiconductors with controlled features. On the other hand,
laser technology is of interest both fundamentally because laser radiation of a semiconductor can lead to different and sometimes opposite results, for example, annealing defects after ion implantation or creating new additional defects and from a device viewpoint , since it can be used for annealing B/n-Si or F/p-Si structures during p-n junction formation which is appropriate for many kinds of microelectronic devices . Moreover, PR-171 supplier our recent investigations have shown that laser radiation can be successfully applied for formation of cone-like nanostructures [7–10] with laser intensity, which do not cause melting of the material. The 1D-graded band gap structure in elementary semiconductors was formed due to quantum confinement effect . Furthermore, it has been shown that irradiation by laser of Si single crystal P-type ATPase with intensity which exceeds melting of material leads to formation of microcones, which are possible to use for solar cells, the so-called black Si . The lack of understanding of the interaction effects of laser radiation
with a semiconductor limits laser technology application in microelectronics . So the aims of this research are to show a new possibility for formation of nanocones and microcones on a surface of elementary semiconductors (Si, Ge) and their solid solution by laser radiation, and to propose the mechanism of cones formation. Materials and methods For the formation of nanocones in the experiments on i-type Ge single crystals with resistivity ρ = 45 Ω cm, N a = 7.4 × 1011 cm−3, N d = 6.8 × 1011 cm−3, where N a and N d are acceptor and donor concentrations, and samples with the size of 16.0 × 3.0 × 2.0 mm3 were used. The samples were mechanically polished with diamond paste and chemically treated with H2O2 and CP-4 (HF/HNO3/CH3COOH in volume ratio of 3:5:3). Different intensities, pulse durations, and wavelengths of nanosecond Nd:YAG laser were used to irradiate the samples (pulse repetition rate at 12.5 Hz, power of P = 1.