Capacitive Properties of Metal–Insulator–Semiconductor Systems Based on an HgCdTe nBn Structure Grown by Molecular Beam Epitaxy

Resumo

The capacitance–voltage (CV) curves of metal–insulator–semiconductor (MIS) systems based on an HgCdTe nBn structure grown by molecular-beam epitaxy on GaAs(013) substrates were studied for the first time in a wide range of frequencies and temperatures. The electron concentration in the near-surface film layer was determined by capacitive measurements and is close to the indium dopant concentration. It was demonstrated that the CV characteristics of MIS systems have a high-frequency behavior in a wide range of measurement conditions, and the product of the differential resistance of the space-charge region and the electrode area in the strong inversion mode is as high as 40 kΩ cm². It was found that the capacitance of the MIS system in the accumulation mode decreases after irradiation at 0.91 μm. This effect may be attributed to the transformation of the band diagram of an abrupt heterojunction triggered by changes in the charge state of defects under irradiation.