34
INTRODUCTION TO PHYSICS OF THE SOLID STATE
Using the GaAs electron effective mass and the heavy-hole effective mass values
from Table B.8, Eq. (2.17) gives m*/mo = 0.059. Utilizing the dielectric constant
value from Table B.ll, we obtain, with the aid of Eqs. (2.18) and (2.19), for GaAs
Eo = 4.6meV
u,E = 1 1 . 8 m
(2.20)
where Eo is the ground-state (n = 1) energy. This demonstrates that an exciton
extends over quite a few atoms of the lattice, and its radius in GaAs is comparable
with the dimensions of a typical nanostructure. An exciton has the properties of
a particle; it is mobile and able to move around the lattice. It also exhibits
characteristic optical spectra. Figure 2.20 plots the energy levels for an exciton
with the ground-state energy Eo = 18 meV.
Technically speaking, the exciton that we have just discussed is a weakly bound
electron-hole pair called a Mott- Wunnier exciton. A strongly or tightly bound
exciton, called a Frenkel exciton, is similar to a long-lived excited state of an atom or
a molecule. It is also mobile, and can move around the lattice by the transfer of the
excitation or excited-state charge between adjacent atoms or molecules. Almost
all the excitons encountered in semiconductors and in nanostructures are of the
Mott-Wannier type, so they are the only ones discussed in this book.
FURTHER READING
K. Boer, ed., Semiconductor Physics, Vols. 1 and 2, Wiley, New York, 2001.
G. Bums, Solid State Physics, Academic Press, San Diego, 1985.
C. Kittel, Introduction to Solid State Physics, 7th ed., Wiley, New York, 1996.
T. I? Martin, T. Bergmann, H. Gohlich, and T. Lange, Chem. Phys. Lett. 172, 209 (1990).
C. I? Poole, Jr. and H. A. Farach, “Chemical Bonding,” in Semiconductor Physics, Vol. 1,
S. Sugano and H. Koizumi, Microcluster Physics, Springer, Berlin, 1998.
P. Y. Yu and M. Cardona, Fundamentals of Semiconductors, 3rd ed., Springer-Verlag, Berlin,
K. Boer, ed., Wiley, New York, 2001, Chapter 2.
2001.
INTRODUCTION TO PHYSICS OF THE SOLID STATE
Using the GaAs electron effective mass and the heavy-hole effective mass values
from Table B.8, Eq. (2.17) gives m*/mo = 0.059. Utilizing the dielectric constant
value from Table B.ll, we obtain, with the aid of Eqs. (2.18) and (2.19), for GaAs
Eo = 4.6meV
u,E = 1 1 . 8 m
(2.20)
where Eo is the ground-state (n = 1) energy. This demonstrates that an exciton
extends over quite a few atoms of the lattice, and its radius in GaAs is comparable
with the dimensions of a typical nanostructure. An exciton has the properties of
a particle; it is mobile and able to move around the lattice. It also exhibits
characteristic optical spectra. Figure 2.20 plots the energy levels for an exciton
with the ground-state energy Eo = 18 meV.
Technically speaking, the exciton that we have just discussed is a weakly bound
electron-hole pair called a Mott- Wunnier exciton. A strongly or tightly bound
exciton, called a Frenkel exciton, is similar to a long-lived excited state of an atom or
a molecule. It is also mobile, and can move around the lattice by the transfer of the
excitation or excited-state charge between adjacent atoms or molecules. Almost
all the excitons encountered in semiconductors and in nanostructures are of the
Mott-Wannier type, so they are the only ones discussed in this book.
FURTHER READING
K. Boer, ed., Semiconductor Physics, Vols. 1 and 2, Wiley, New York, 2001.
G. Bums, Solid State Physics, Academic Press, San Diego, 1985.
C. Kittel, Introduction to Solid State Physics, 7th ed., Wiley, New York, 1996.
T. I? Martin, T. Bergmann, H. Gohlich, and T. Lange, Chem. Phys. Lett. 172, 209 (1990).
C. I? Poole, Jr. and H. A. Farach, “Chemical Bonding,” in Semiconductor Physics, Vol. 1,
S. Sugano and H. Koizumi, Microcluster Physics, Springer, Berlin, 1998.
P. Y. Yu and M. Cardona, Fundamentals of Semiconductors, 3rd ed., Springer-Verlag, Berlin,
K. Boer, ed., Wiley, New York, 2001, Chapter 2.
2001.