Patent ID: 8093139
Filing Date: 2012-01-10
Classification: B82Y,G02B,H01L

Abstract:
1. A method of light-assisted fabrication of nanocomposite semiconductor materials and electronic, optoelectronic, photonic and plasmonic devices incorporating metal or semiconductor aligned nanowires self-assembled in matrix semiconductor material comprising the steps of selecting a compound matrix semiconductor material, including GaAs, AlGaAs, InGaAsP, InP, GaP, GaN, ZnSe, ZnS, ZnO, HgCdTe, CdTe, InSb, GaSb, InAs, AgBr, AgF, AgCl, CdS, comprising charged self-interstitial defect atoms, from which the nanowires are to be self-assembled, or a matrix semiconductor material, including Si, Ge and various organic semiconductors, in which foreign charged interstitial defect atoms can be artificially introduced for self-assembling from them the nanowires, creating sufficiently strong electric field by applying voltage across the semiconductor material to move the charged interstitial defect atoms inside the matrix semiconductor material in the direction of nanowire alignment and to deplete from free charge carriers the region of the matrix semiconductor material where nanowires are to be self-assembled, illuminating the semiconductor material with light to photogenerate free charge carriers in the conduction and valence band of the semiconductor material in the regions where nanowires are to be self-assembled using the light at wavelength having sufficiently strong absorption, including the light at wavelength of fundamental absorption in the matrix semiconductor material and the light at wavelength slightly above edge of the spectral region of fundamental absorption, which can deeply penetrate inside the semiconductor material, selecting the light intensity that ensures photogeneration of enough free charge carriers for transformation of the charged interstitial defect atoms into neutral nanowire material, but does not generate too many free charge carriers preventing penetration of said electric field into the matrix semiconductor material due to field screening effect, creating an additional fast oscillating electric field in the matrix semiconductor material having frequency exceeding the inverse lifetime of the photogenerated free charge carriers and having amplitude ensuring capture of the photogenerated free charge carriers from corresponding conduction or valence band by the charged interstitial defect atoms resulting in formation of neutral nanowire material using such means as modulating the applied voltage or irradiating the semiconductor material with electromagnetic radiation, continuing the process at room temperature or at elevated temperature until the aligned nanowires of required size are self-assembled.