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.

For the first time, a new PL band at 1.8718 eV is observed after irradiation of Cd1-xZnxTe (x = 0.1) crystal by Nd:YAG laser at intensity 12.0 MW/cm2. The origin of this PL band we connect with formation of strongly enriched layer by Zn atoms at the irradiated surface of the sample due to a themogradient effect. Self-organizing structures of nanometer size are observed on the surface of a CdZnTe crystal (x = 0.1) irradiated by strongly absorbed Nd:YAG laser radiation at intensities 4.0-12.0 MW/cm2. The effect of exciton quantum confinement manifested by a shift to higher energies of the A0,X exciton line in the photoluminescent spectrum is present in structures of 10–15 nm in diameter at the top of nanohills. A graded band gap structure with optical window is formed on the top of nanohills.

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Self‐organizing structures of nanometer size are observed on the surface of CdZnTe crystal irradiated by strongly absorbed Nd:YAG laser radiation (LR) at intensities within 4–12 MW/cm2. The effect of exciton quantum confinement manifested by a shift to higher energies of the A0,X exciton band of the photo‐luminescent spectrum is present in structures of 10–15 nm in diameter at the top of nano‐hills. A graded band gap structure with optical window is formed at the top of nano‐hills. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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