SEMICONDUCTOR DEVICE PHYSICS AND DESIGN

10.4. QUANTUM INTERFERENCE EFFECTS 499

A eik • 1 r

A eik • 2 r

A (eik 1 + eik • 2 d)

Source Drain

path 1

path 2

GaAs

AlGaAs

Source Gates

Drain

Ec(AlGaAs)

• ––

EF

Ec

• –

– – EF

EF

Electron

barrier

(a)

(b)

Electron wave interference

Split gate device

Figure 10.8: (a) A schematic of a coherent electron beam interference structure. (b) A schematic
of a split-gate transistor to exploit quantum interference effects. Electrons propagate from the
source to the drain under the two independently controlled gates in the 2-dimensional channel of
AlGaAs/GaAs as shown.

energy in the quantum well)

EF=Ec+

^2 k^2

2 m∗

(10.4.4)

By changing the position ofEF, one can alter thek-value. Thus one can develop quantum
interference transistors.