Two additional electrical contact layers are needed to carry the electric current out to an external load and back into the cell, thus completing an electric circuit.
Semiconductors in thicknesses of about one-hundredth of a centimetre or less can absorb all incident visible light; since the junction-forming and contact layers are much thinner, the thickness of a solar cell is essentially that of the absorber.
In effect, the electric field gives a collective motion to the electrons that flow past the electrical contact layers into an external circuit where they can do useful work.
Typical PL emission from contact layers and QW region under 0.52 V and 19 T (b).
Those carriers can be either photo-created at the contact layers or originate from doping.
The nanoscale printed contact layers made on nanocellulose paper assure high output power and abrasion durability.
The contact layers are created by 2D inkjet printing with precisely patterned grating structure.
Figure 2 shows the current voltage (I V) characteristics of the Cr/ITO contact layers, measured between ohmic pads.
Wires were soldered to the contact layers of all four samples and connected to sample holder pins.
The PL spectra include the emission from the QW and the contact layers, and both are voltage dependent.
Figure 2 Voltage dependence of PL for QW (a) and contact layers (d) under zero magnetic field and polarization resolved PL for QW (b,c) and contact layers (e,f) under 19 T. Figure 2d-f presents the voltage dependence of the PL from the GaAs contact layers.
