Contents
What is meant by thermal equilibrium in semiconductor?
Semiconductor in thermal equilibrium means it must not be exposed to the external temperature.
What is no and PO in semiconductor?
When a semiconductor is not doped, NA = 0 and ND = 0, the semiconductor is intrinsic and no = po = ni. This also occurs when NA and ND are approximately equal, or ni >> |ND – NA|. 2. The equations for the carrier concentrations for a p-type semiconductor, NA >> ni and ND = 0, can be simplified.
What is Ni for silicon?
1. A silicon sample at room temperature has an intrinsic carrier concentration of ni = 5×109 cm-3.
How do you know if a semiconductor is in equilibrium?
The number of carriers in the conduction and valence band with no externally applied bias is called the equilibrium carrier concentration. For majority carriers, the equilibrium carrier concentration is equal to the intrinsic carrier concentration plus the number of free carriers added by doping the semiconductor.
Which is N-type semiconductor?
An n-type semiconductor is an intrinsic semiconductor doped with phosphorus (P), arsenic (As), or antimony (Sb) as an impurity. Silicon of Group IV has four valence electrons and phosphorus of Group V has five valence electrons. * This free electron is the carrier of an n-type semiconductor.
Is human body in thermal equilibrium with the environment?
Heat, Cold, and Performance: we are still remarkably ignorant of the body’s thermoregulatory mechanisms! The living body constantly produces heat and this must be transferred to the environment. Heat balance (thermal equilibrium) is the balance between the rate of heat production and the rate of heat loss.
What happens when thermal equilibrium is reached?
When two objects are in thermal equilibrium they are said to have the same temperature. During the process of reaching thermal equilibrium, heat, which is a form of energy, is transferred between the objects.
How does NI change with temperature?
As the temperature is decreased, electrons do not receive enough energy to break a bond and remain in the valence band. Therefore, lowering the temperature causes a decrease in the intrinsic carrier concentration, while raising the temperature causes an increase in intrinsic carrier concentration.
How is the semiconductor in equilibrium with time?
Equilibrium, or thermal equilibrium, implies that no external forces such as voltages, electric fields, magnetic fields, or temperature gradients are acting on the semiconductor. All properties of the semiconductor will be independent of time in this case.
Which is a special thing about thermal equilibrium?
The special thing about thermal equilibrium is that the generation is due solely to the surrounding heat. This means that all the generation in the semiconductor is thermal generation. In addition, there is no current in a thermal equilibrium semiconductor. It is only in thermal equilibrium that we discuss Fermi levels.
When do we discuss the Fermi level in thermal equilibrium?
It is only in thermal equilibrium that we discuss Fermi levels. When a device is not in thermal equilibrium but is in steady state (with no current), we have what is called a “quasi-Fermi level” which is simply the Fermi level that would be computed if the non-equilibrium carrier concentration is taken into consideration instead.