Environmental Engineering Reference
In-Depth Information
of materials for nanotechnology research and applications. In
rare situations, crystalline materials (e.g., ZnSe) are also possible
from this technique. The deposition of consecutive semiconducting
layers enables in some cases the fabrication of complete elec-
tronic devices within one electrolyte, as explained later in this
chapter.
3.3 Strengths and Advantages of Electrodeposition
3.3.1
Simplicity, Low-Cost, Scalability, and
Manufacturability
Electrodeposition is usually carried out in normal laboratory
conditions without the requirement of a vacuum system. Low-
temperature growth saves energy, but most of the electrodeposited
material layers need a post-deposition annealing step at an
optimised elevated temperature of around 400
◦
C in a suitable
atmosphere for approximately 15 minutes. The low-temperature
electrodeposition allows the fabrication of abrupt junctions, min-
imisinginteractions at these interfaces during growth.
The most attractive feature is the low cost when compared
to other semiconductor growth techniques. A well-established
MBE or MOCVD system needs an initial cost in the order of
£
1
million, and these systems have limitations as to the number
of different materials which can be grown. These techniques
have been developed in the past to grow small wafers of high-
quality semiconductors to fabricate microelectronic devices. These
techniques serve that purpose well although the costs are high.
In the case of electrodeposition, a computerised potentiostat costs
about
£
6,000 and a wide range of materials can be grown. The
change of the electrolytic cell provides the conditions necessary for
the growth of a new material.
For macroelectronic devices, such as solar panels and large-
area display devices, scalability is very important. In the case of
electrodeposition, it is possible to use large tanks as electrolytic
baths and, therefore, large-area thin films can be produced. As
shown in Fig. 3.2, batches of a number of large plates can
