Environmental Engineering Reference
In-Depth Information
Figure 3.8
Photoluminescencespectraobtainedfor(a)ZnSelayersgrown
by MBE on GaAs (100) surfaces and (b) electrochemically deposited ZnSe
layers on glass/ITO substrates [15].
bandgaps [15]. The results obtained are shown in Fig. 3.8 for
comparison. It is evident that there are at least five defect levels in
the observedenergy range for MBE-grown ZnSe, but incomparison,
there is only one defect level for electrodeposited ZnSe layers. The
only difference is the broadened peak at 0.75 eV, possibly due to
a distribution of energy levels at the vicinity of that defect level.
However, the overall observation is that the electrodeposited layers
possess much cleaner bandgaps than MBE-grown ZnSe layers used
in these investigations. This example highlights the possibility of
