Environmental Engineering Reference
In-Depth Information
withthicknessesofafewmicrons,thesituationbecomesevenmore
complex due to the effects of surface states.
Table 1.2 The most common elements used for the production of
semiconductors, with their groups assigned in the Periodic Table
Group I
Group II
Group III
Group IV
Group V
Group VI
Cu
Zn
B
C
N
S
Ag
Cd
Al
Si
P
Se
Ga
Ge
As
Te
In
Sn
Sb
O
Table1.3 Asummaryofsemiconductormaterialfamiliesavailableforuse
in PV devices
Semiconductor Family
Examples of Semiconductors
Elemental semiconductors
C, Si, Ge
III-V semiconductors
AlN, AlP, AlAs, AlSb
GaN, GaP, GaAs, GaSb
InN, InP, InAs, InSb
II-VI semiconductors
ZnS, ZnSe, ZnTe, ZnO
CdS, CdSe, CdTe, CdO
Ternary compound semiconductors
CuInSe
2
(CIS), Cd
x
Mn
(1
−
x
)
Te,
Cd
x
Hg
(1
−
x
)
Te, Al
x
Ga
(1
−
x
)
As
Quaternary compound semiconductors
CuInGaSe
2
(CIGS), AgInGaSSe, CuZnSnSSe
1.4 Electronic Devices Used for Solar Energy Conversion
Once the suitable solar energy materials are selected, the optimum
growth conditions have been established, and the materials are
fully characterised for their mechanical, structural, optical and
electrical properties, the next task is to design and fabricate an
effectiveelectronicdevicecapableofcreatingandseparatingphoto-
generated charge carriers before they recombine. This requires a
strong built-in electric field within the electronic device. The heart
of a PV device is, therefore, one or more interfaces created by
combining suitable semiconductors and two electrical contacts to
extract charge carriers from these devices. Therefore, in a typical
PV device, several interfaces can be incorporated, made out of
