The top-down approach limits the dimensions of devices to what is technically achievable using

Fig. 11 (a) Formation of ideal DBRT device structures, with InP barrier thicknesses of 5 nm
surrounding a central QD, which is 15 nm thick; (b) calculated energy band structure; 
and (c) resulting I-V characteristics of the device. The sharp resonant features, with 
peak-to-valley rations as high as 50:1, are as predicted by the energy band modeling
27
.
(© American Institute of Physics 2002.)
Fig. 12 The design and performance of a SET in a nanowire: (a) shows the I-V dependence
for two settings of the gate, one for complete Coulomb blockade and one where the
blockade is fully lifted; (b) shows the periodic response and the control of the number of
electrons on the island using the gate; (c) and (d) show comparison between experiment
and theory for the stability diagram of the SET, in which the current derivative (dI/dV
SD
) is
plotted as function of the gate (V
G
) and source-drain voltage (V
SD
). The horizontal chain
of (tilted) diamonds are the areas of complete Coulomb-blockade of the current.
Modeling of the device was made using SIMON simulation of nanostructures
28
. (©
American Institute of Physics 2003.)

---

REVIEW
FEATURE
up approach for making perfect arrays of active devices, for
field emission arrays and photonic band gap structures.
Outlook
The possibility of forming complex nanowire structures has
been demonstrated over the last two years, promising the
parallel fabrication of large numbers of such devices at
predefined locations. I believe this is a precondition for
several major breakthroughs in nanoelectronics and
photonics, and that these technologies are, in general,
opening up new opportunities in materials research. 
I conclude with a fantasy picture (Fig. 14) of how complex
nanowire devices may be made fully compatible and
integrated with established technologies, hence offering
opportunities for further progress towards quantum
electronics and quantum photonics applications. 
MT
Acknowledgments
The work presented in this talk was obtained through contributions from many students
and colleagues: Jonas Ohlsson and Ann Persson (CBE growth); Werner Seifert and Magnus
Borgström (MOVPE growth); Claes Thelander, Mikael Björk, and Thomas Mårtensson
(device fabrication and investigations); Nikolay Panev and Niklas Sköld
(photoluminescence studies); Reine Wallenberg, Torsten Sass, and Magnus Larsson (TEM
analysis); Knut Deppert, Martin Magnusson, and Martin Karlsson (aerosol technology);
and Hongqi Xu and Martin Persson (theoretical work). Our research is supported by the
Swedish Foundation for Strategic Research and the Swedish Research Council.
October 2003
3 1
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