Impurity band in lithium-diffused and annealed GaAs: Conductivity and Hall effect measurements

Abstract

Originally n-type Si-doped GaAs turns p-type after Li indiffusion and consequent annealing at 200-600°C. Temperature-dependent conductivity and Hall effect measurements carried out in the temperature range 30-300 K reveal conduction via impurity bands made up of shallow acceptors in addition to the valence-band conduction. Li diffusion into GaAs reduces the free-carrier concentration which leads to electrical resistivity as high as 10 7 ⍀ cm. Annealing highly resistive samples at temperatures above 200°C significantly decreases the room-temperature resistivity to 0.1-1 ⍀ cm, depending on the annealing temperature. For samples annealed at 300Ϫ400°C we observe a metallic-type conduction which contributes to the conduction even at room temperature. In samples annealed at 500-600°C the temperature dependence of the resistivity indicates that impurity conduction sets in at temperatures below 100 K. We discuss this conduction change in relation to enhanced gallium vacancy (V Ga ) and gallium antisite ͑Ga As ) concentration in Li indiffused and annealed samples.

Electrical properties of N-doped ZnO grown on sapphire by P-MBE

“…We found that the conductivity increased with increasing temperature; it seemed to indicate that the transport mechanism in the sample was by holes in valence band. The conductivity (σ ) from holes in valence band can be described by the following equation [10,11]: where A is a temperature-independent constant, E A is the acceptor activation energy, k is the Boltzmann constant and T is the thermodynamic temperature. The dash line in figure 2 is a fit to σ versus T data by equation (1).…”

“…The temperature dependence of conductivity was fitted by the mix of band and nearestneighbour hopping conduction mechanisms. In such a case, the relationship between the total conductivity and temperature can be expressed as [10,11] σ total = σ band + σ nn = A exp(−E A /kT ) + B exp(−E nn /kT ).…”

Ultrahigh Conductivity in Two-Dimensional InSe via Remote Doping at Room Temperature

“…The black dashed lines present the isolines of different conductivity value, σ, which is defined as σ = nqμ . Here the values of carrier concentration, mobility, and conductivity are taken from literature. − …”