Contents
Why electrons have greater mobility than holes in semiconductor material?
In a semiconductor, why is mobility of electrons greater than mobility of holes. Answer: Free electrons, those are moving from one atom to another are in conduction band. Hence electron at Conduction band moves faster and has more mobility than holes in valance band.
What is the speed of electron and hole?
Electric field dependence and velocity saturation For example, the value of vsat is on the order of 1×107 cm/s for both electrons and holes in Si. It is on the order of 6×106 cm/s for Ge. This velocity is a characteristic of the material and a strong function of doping or impurity levels and temperature.
What is the difference between a hole and electron?
Unlike an electron which has a negative charge, holes have a positive charge that is equal in magnitude but opposite in polarity to the charge an electron has. Holes can sometimes be confusing as they are not physical particles in the way that electrons are, rather they are the absence of an electron in an atom.
Which has better mobility electrons or holes?
Since holes are subjected to the stronger atomic force pulled by the nucleus than the electrons residing in the higher shells or farther shells, holes have a lower mobility. because electron effective mass is smaller than holes therefore mobility of electron is higher than holes.
Why do holes have lower mobility?
Conduction electrons (free-electrons) travel in the conduction band and valence electrons (holes) travel in the valence band. Since holes are subjected to the stronger atomic force pulled by the nucleus than the electrons residing in the higher shells or farther shells, holes have a lower mobility.
Are electrons heavier than holes?
Hence the mass of holes is greater than the mass of electrons by quantum computations of allowed bands energy (which in turn comes from the structure of the crystal and the structure of the composing atoms themselves).
Do electrons and holes have the same mass?
The concept of effective mass follows from physicists’ love for simple relations such as Ohm’s law (current density = conductivity x electric field intensity) or Newton’s second law of motion (acceleration = force / mass). From this follows that the hole effective mass is often larger than the electron effective mass.
Why do electrons have greater mobility than holes in a semiconductor?
High curvature results in carriers with lower effective mass and vice versa. In most of the semiconductors the valence bands generally have low curvature than conduction bands, which eventually results in holes with high effective mass than electrons.
Why are electrons moving faster than holes in the valence band?
Thus it is easier for the electrons in the conduction band to move from ion to ion than it is for the holes in the valence band to move. In other words, the electrons in the conduction band move faster than the holes in the valence band do.
Why do electrons move in the opposite direction to the hole?
As the hole moves farther to the right, electrons must move left to accommodate the hole. The hole in the absence of an electron in the valence band due to P-type doping. It has a localized positive charge. To move the hole in a given direction, the valence electrons move in the opposite direction.
Which is an electron acceptor with an excess of holes?
Since holes are positive charge carriers, an electron acceptor dopant is also known as a P-type dopant. The P-type dopant leaves the semiconductor with an excess of holes, positive charge carriers. The P-type elements from group IIIA of the periodic table include boron, aluminum, gallium, and indium.