If the temperature of gallium arsenide (GaAs) is increased, its electrical conductivity will ?

Gallium arsenide (GaAs) is a semiconductor compound formed from gallium (Ga) and arsenic (As). It has a zinc blende crystal structure and behaves as a direct band gap semiconductor widely used in modern electronic and optoelectronic devices such as LEDs, solar cells, and microwave circuits.

In semiconductors like GaAs, electrical conductivity depends on the number of free charge carriers (electrons and holes). At low temperatures, very few electrons have enough energy to cross the band gap (≈1.43 eV at 300 K) from the valence band to the conduction band, so conductivity is low. As temperature increases, the thermal energy available to electrons also increases, enabling more electrons to move into the conduction band.

The relationship between temperature and conductivity in semiconductors is opposite to that of metals. In metals, conductivity decreases with temperature because lattice vibrations scatter conduction electrons. In semiconductors like GaAs, conductivity increases because the number of thermally generated carriers rises exponentially with temperature according to the relation:

σ = neμₑ + p eμₚ

where:

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  σ = electrical conductivity

  
  


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  n and p = electron and hole concentrations

  
  


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  μₑ and μₚ = their respective mobilities

  
  

Although mobility slightly decreases with temperature, the sharp rise in carrier concentration dominates, leading to a net increase in conductivity.

Therefore, when the temperature of gallium arsenide (GaAs) is increased, its electrical conductivity increases significantly. This property is essential in understanding how semiconductor devices operate under varying thermal conditions and is a fundamental concept in solid-state and physical chemistry.