Hi All .
Recently, I conducted Hall measurement experiments at high temperatures on highly p-doped diamond with a doping concentration of 2.5×10^20 cm−3
During these experiments, I observed two key phenomena:
Carrier Concentration: As the temperature increased, the carrier concentration decreased.
Resistivity: Despite the decrease in carrier concentration, the resistivity of the material decreased with increasing temperature.
Resistivity decreasing is logical. But why the carrier concentrations are decreasing?.
The decrease in charge carrier concentration in diamonds at high temperatures can be attributed to several physical factors. In general, when a diamond is heated, the thermal energy increases the movement of atoms and can affect the distribution of electrons and holes, which are the charge carriers in the material. One reason may be the rearrangement of atoms within the crystal structure of diamond, which can lead to a reduction in charge carrier mobility. In addition, at high temperatures, processes such as diffusion and recovery can occur, which affect the defect structure and charge carrier distribution1. In addition, diamond luminescence can play a significant role. For example, synthetic diamonds subjected to strong UV excitation can exhibit luminescence that indicates the presence of specific growth regions or treatments2. These luminescences can be influenced by temperature and alter the charge carrier concentration. In summary, the decrease in carrier concentration in diamonds at high temperature is a complex phenomenon involving the atomic and electronic dynamics of the material, and can be studied through advanced detection methods such as luminescence.
2.5 × 10^20 cm−3? What is the active percentage of doping at this magnitude? Such high impurity concentrations in semiconductors may generate significant scattering during carrier transport.
In a conventional Hall test, errors are canceled using forward and reverse tests. However, these operations may yield unexpected results when employing bad electrodes or unique samples. For example, if one of the electrodes offers a Schottky contact, the voltammetric properties will differ in the forward and reverse directions. Please review the voltammetric data for each electrode and estimate the sample's hole concentration accurately.
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