What is the barrier potential for silicon and germanium?

What is the barrier potential for silicon and germanium?

The barrier potential of germanium is approximately 0.3 V, and of silicon is 0.7 V. In order to produce current conduction, the barrier potential of a P-N junction must be overcome by an external voltage source.

What is the barrier potential of silicon?

0.7V
In the case of silicon, its potential barrier is 0.7V. That means if we need to work a silicon diode, then we must apply a voltage of minimum 0.7V to make it work.

Why the reverse current in Ge diode is greater than Si diode?

The number of minority charge carriers generated in the germanium diodes is greater than the silicon diodes. Hence, the reverse saturation current in the germanium diodes is greater than the silicon diodes.

Why is germanium more temperature dependent than silicon?

Germanium is more temperature sensitive than silicon because it has a smaller band gap. Even at moderate temperature, a substantial number of electrons in germanium are produce from thermal generation. For example at about 120 C, the concentration of electrons and holes from thermal generation is > 1E15.

What causes barrier potential?

The potential difference required for the electrons to be passed across the electric field is called the potential barrier. The barrier potential of a P-N junction depends on the type of material, amount of doping and temperature of the semiconductor. For silicon it is about 0.7V, for germanium, it is about 0.3V.

What is the typical value of the barrier potential for a silicon diode and germanium diode?

Typically at room temperature the voltage across the depletion layer for silicon is about 0.6 – 0.7 volts and for germanium is about 0.3 – 0.35 volts. This potential barrier will always exist even if the device is not connected to any external power source, as seen in diodes.

Why the reverse saturation current in a silicon diode is much smaller than that in a comparable Germanium diode?

Energy gap between conduction band and valance band in case of germanium is 0.67eV but in case of silicon it is 1.1eV. And as we know reverse saturation current produces due to holes so more the number of holes in case of germanium in its valance band and more the reverse saturation current than silicon.

Why is the reverse current in a silicon diode much smaller than that in a comparable Germanium diode?

At room temperature, Silicon crystal has fewer free electrons than Germanium crystal. This implies that silicon will have much smaller Collector cut off current than Germanium. The variation of Collector cut off current with temperature is less in Silicon compared to Germanium.

Why silicon is preferred over germanium in the manufacturing of SCR?

The variation of Collector cut off current with temperature is less in Silicon compared to Germanium. However, Silicon crystals are not easily damaged by excess heat. Peak Inverse Voltage ratings of Silicon diodes are greater than Germanium diodes. Si is less expensive due to the greater abundance of element.

What is the difference between germanium and silicon?

Silicon is a chemical element with atomic number 14 and chemical symbol Si while germanium is a chemical element with atomic number 32 and chemical symbol is Ge. The key difference between silicon and germanium is that Germanium has d electrons, but Silicon does not have any d electrons.

What is barrier potential and depletion region?

Deplection region is a region created around the p-n junction which is devoid of free charge carriers and has immobile ions. Potential barrier is a potential difference or junction voltage developed across the junction due to migration of majority carriers across it when p-n junction is formed.

What are the disadvantages of silicon as compared to germanium?

The disadvantage of silicon as compared to germanium is that potential barrier of silicon diode (0.7V) is more than that of germanium diode (0.5V). This means that higher bias voltage is required to cause current flow in a silicon diode circuit.

What is the difference between silicon diode and germanium diode?

For example, the PIV ratings of silicon diodes are in the neighbourhood of 1000V whereas the PIV ratings of germanium diodes are close to 400V. The disadvantage of silicon as compared to germanium is that potential barrier of silicon diode (0.7V) is more than that of germanium diode (0.5V).

What is the outer energy level of silicon and germanium?

Silicon and germanium, are both in the same group (group 14) of the periodic table. Hence, they have four electrons in the outer energy level.

What is the oxidation number of silicon in germanium?

Silicon and germanium, are both in the same group (group 14) of the periodic table. Hence, they have four electrons in the outer energy level. They occur in two oxidation states, +2 and +4. Silicon and germanium share similar physical and chemical characteristics, since both are metalloids.