818 Handbook of Self Assembled Semiconductor Nanostructures for Novel Devices in Photonics and Electronics
of a solar cell with an impurity level in the semiconductor band gap under ideal conditions.
Under these ideal conditions, it was argued that an effi ciency of 63.1% was possible instead of
the 40.7% predicted in the Shockley and Queisser model limit, as discussed by Werner et al. [57] .
While this analysis of an idealized system with an impurity having an energy in the semiconduc-
tor band gap predicts high effi ciencies, the implementation of such a scheme through the use of
quantum dots to provide the intermediate level (or band) has resulted recently [55] in the obser-
vation and conclusion that the absorption of light in a ten-layer system is low and that increas-
ing the number of layers might lead to material defects.
28.6 Summary
This chapter has summarized a number of major trends underlying the continuing effort to real-
ize practical optoelectronic, electronic and information-processing devices based on ensembles of
quantum dots assembled in a variety of matrix materials. The great diversity of such structures
has opened the possibility of numerous device applications and stimulated research underlying
photoluminescent devices, light-emitting diodes, displays, photodetectors, photovoltaic devices,
solar cells and novel spin-based information processing devices. It is expected that research
underlying these applications will continue to thrive due to the enormous number of possible
device embodiments possible with colloidal quantum dots and available matrix materials.
References
1. I. Bockelmann and G. Bastard , Phonon scattering and energy relaxation in two-, one-, and zero-
dimensional electron gases , Phys. Rev. B 42 ( 14 ) , 8947 – 8951 ( 1990 ) .
2. T. Inoshita and H. Sakaki , Electron relaxation in a quantum dot: signifi cance of multiphonon
processes , Phys. Rev. B 46 ( 11 ) , 7260 – 7263 ( 1992 ) .
3. J.-P. Leburton , R.C. Fonseca , S. Nagaraja , J. Shumway , D. Ceperley , and R.M. Martin , Electronic
structure and many-body effects in self-assembled quantum dots , J. Phys. Cond. Matt. , 11 , 5953 –
5967 ( 1999 ) .
4. P. Bhattacharya , S. Ghosh , and A.D. Stiff-Roberts , Quantum dot optoelectronic devices , Ann. Rev.
Mat. Res. 34 , 1 – 40 ( 2004 ) .
5. M.S. Skolnick and D.J. Mowbray , Self-assembled semiconductor quantum dots: fundamental phys-
ics and device applications , Annu. Rev. Mater. Res. 34 , 181 – 218 ( 2004 ) .
6. P.K. Bhattacharya and S. Ghosh , Tunnel injection In
0.4
Ga
0.6
As/GaAs quantum dot lasers with
a 15 GHz modulation bandwidth at room temperature , Appl. Phys. Lett. 80 ( 19 ) , 3482 – 3484
( 2002 ) .
7. C. Blakesley , P. See , A.J. Shields , B.E. Kardynal , P. Atkinson , I. Farrer , and D.A. Ritchie , Effi cient
single photon detection by quantum dot resonant tunneling diodes , Phys. Rev. Lett. 94 , 067401 –
067414 ( 2005 ) .
8. A.J. Shields , M.P. O’Sullivan , I. Farrer , D.A. Ritchie , R.A. Hogg , M.L. Leadbeater , C.E. Norman , and
M. Pepper , Detection of single photons using a fi eld-effect transistor gated by a layer of quantum
dots , Appl. Phys. Lett. 76 ( 25 ) , 3673 – 3675 ( 2000 ) .
9. J. Pacifi co , J. Jasieniak , D. Gomez , and P. Mulvaney , Tunable 3D arrays of quantum dots: synthesis
and luminescent properties , Small . 2 ( 2 ) , 199 – 203 ( 2006 ) .
10. J. Zhao , J. Zhang , C. Jiang , J. Bohnenberger , T. Basche , and A. Mews , Electroluminescence from
isolated CdSe/ZnS quantum dots in multilayered light-emitting diodes , J. Appl. Phys. 96 , 3206 –
3210 ( 2004 ) .
11. T. Kato , A. Okazaki , and S. Hayase , Latent gel electrolyte precursors for quasi-solid dye sensitized
solar cells , Chem. Commun. 3 , 363 – 365 ( 2005 ) .
12. E.P.A.M. Bakkers , A.W. Marsman , L. Jenneskens , and D. Vanmaekelbergh , Distance-dependent
electron transfer in Au/spacer/Q-CdSe assemblies , Angew. Chem. 39 ( 13 ) , 2297 – 2299 ( 2000 ) .
13. M. Brumer , A. Kigel , L. Amirav , A. Sashchiuk , O. Solomesch , N. Tessler , and E. Lifshitz , PbSe/PbS
and PbSe/PbSe
x
S
1 ⫺ x
core–shell nanocrystals , Adv. Funct. Mat. 15 , 1111 – 1116 ( 2005 ) .
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