Admittance dependences of the mid-wave infrared barrier structure based on HgCdTe grown by molecular beam epitaxy

The admittance of nBn structures based on HgCdTe grown by molecular beam epitaxy (MBE) on GaAs (013) substrates was studied. The measurements were performed in the temperature range of 10–310 K at the frequencies of 0.5–2000 kHz. The content of CdTe in the absorbing layer was 0.36, and the content in the 210 nm thick barrier layer was 0.84. Equivalent circuits of nBn structure for various temperature and voltage ranges are proposed. The calculated frequency dependences of the admittance are in good agreement with the experimental data. The dependences of the values of the equivalent circuit elements on the area of nBn structure and on temperature are established. It is shown that measurements of the capacitance-voltage characteristic of nBn structure based on MBE HgCdTe in a wide range of conditions allow determining dopant concentration in the absorbing layer. At near room temperatures, features of the voltage dependences of the admittance, which related to the defect level recharge near the heterojunction between the absorbing and barrier layers, were found