ABSTRACT
In Section 5.1, we defined the ideal 1DES and introduced realistic
1DESs that can be fabricated from various types of semiconductors.
If the free electron motion in a 1DES is frozen by further confine-
ment in the z-direction (the direction in which electrons freely move in the 1DES), then the system is called a zero-dimensional electron
system (0DES). Figure 6.1 shows a conceptual diagram of a 0DES. It
is basically the ideal 1DES of Fig. 5.1 with two walls added to the
figure to denote the potential confinement, blocking electron mo-
tion in the z-direction. Electrons are captured between the potential walls and cannot move freely even in the z-direction. The only way for the electrons between the two walls to be released is either by
quantummechanical tunneling through thewalls or by jumping over
the walls. Classically, the most important energy that these 0DES
electrons have is the electrostatic energy determined by the total
charge (the self potential energy) and the electrostatic potential of
the system (the external potential energy).
