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Home Material Sciences Laser-Formed Ordered Nanostructures in Semiconductors

Laser-Formed Ordered Nanostructures in Semiconductors

Introduction

  • The high-power laser irradiation of semiconductor surface could change the morphology of the surface layer up to formation of low-dimensional structures.
  • The question of intensity or dose dependence of nanostructure formation on the surface of semiconductors is still open and actual.

Purpose

  • To study the fundamental and applied problems of interaction of laser radiation with semiconductors.
  • To determine the optimal conditions for formation of nanodimensional structures on semiconductor surface using pulsed laser radiation.

Advantages of laser technology

  • Locality and precision of treatment and manufacturability of procedure.
  • Avoiding heating of the bulk of crystals and modification only a thin surface layer.
  • Formation of nanodimensional structures in short time with given locality as in depth and as on surface of crystals.
  • Formation of nanodimensional structure in the semiconductor crystal lattice, which acts as matrix and play an essential role at each stage of process.

Intensity dependence of nanostructure formation


Fourier transformation of AFM image



Conclusion: The first stage of self-organization (selection of lattices on period) and partial angular self-organization process occur after laser irradiation of 12 MW/cm2.

Dose dependence of nanostructure formation


Dimensional effects due to nanostructures


Atom-force microscopy image in scale
of 30х30 µm of (111) CdTe surface irradiated
with dose D = 0.9 J/cm2.


Raman spectra
1- initial crystal; 2, 3 - irradiated crystals by the
D1 dose before (2) and (3)- after washing of a Te layer;
4, 5 - irradiated rystals by the D2 dose
before (4) and after (5) washing of a Te layer.

Areas of Application

Undoped, plate-like, and dislocation free (Nd ~ 102 cm–2) p-CdTe (111) oriented crystal wafers

CdTe nanocrystals applications:

  • as a material in the fabrication of room-temperature fast-response modulators of the intensity of luminous fluxes
  • as a substrate material for CdHgTe layers.
  • Therefore, the fabrication of ordered structures on the surface of CdTe crystals may possibly help to solve problems related to the growth of nanodimensional CdHgTe layers .

Conclusions

  • The use of laser techniques to fabricate alternate semiconductor materials looks very prospective.
  • Analysis of experimental data’s allowed us to establish optimum regime of laser irradiation at which evenly distributed periodic nanostructures with minimal lateral sizes and with a period 100 nm are formed on a surface of CdTe crystals.

Contact Details

Aliya Baydulayeva
Organization: Institute of Semiconductor Physics , NASU.
Address: 41, Nauky ave., Kyiv, 03028, Ukraine.
(380-44) 525 4020.
This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

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