LED and Laser diode Characteristics Apparatus
Product Code : JA-PLE-7969
LED and Laser diode Characteristics Apparatus
A light-emitting diode (LED) is a semiconductor light source.
Like a normal diode, the LED consists of a chip of semiconducting material doped with impurities to create a p-n junction.
As in other diodes, current flows easily from the p-side, or anode, to then-side, or cathode, but not in the reverse direction.
When an electron meets a hole, it falls into a lower energy level and releases energy in the form of a photon.
The wavelength of the light emitted, and therefore its colour depends on the band gap energy of the materials forming the p-n junction.
Typical I-V Characteristics of LED in forwarding bias are shown in the fig.
Charge-carriers-electrons and holes - flow into the junction from electrodes with different voltages.
A laser diode, like many other semiconductor devices, is formed by doping a very thin layer on the surface of a crystal wafer.
A laser diode is a laser where the active medium is a semiconductor similar to that found in a light-emitting diode.
The crystal is doped to produce an n-type region and a p-type region, one above the other, resulting in a p-n junction, or diode.
Procedure:
LEDs are connected in forward bias arrangement and applied a voltage across LED is varied & corresponding current is measured.
The result is tabulated and plotted on the graph.
In second part voltage applied across Laser diode is varied.
Its corresponding output is measured & plotted.
