Temperature and field dependences of parameters of the equivalent circuit elements of MIS structures based on MBE n-Hg0.775Cd0.225Te in the strong inversion mode

A technique is proposed for the determining the parameters of the equivalent circuit elements in strong inversion mode using the measurement results of the admittance of MIS structures based on n-Hg0.775Cd0.225Te grown by molecular beam epitaxy. It is shown that at 77 K and frequencies above 10 kHz, the capacitancevoltage characteristics of MIS structures based on n-Hg0.775Cd0.225Te with a near-surface graded gap layer have a high-frequency behavior with respect to the recharge time of surface states located near the Fermi level of intrinsic semiconductor. It is established that the electron concentration in the near-surface graded-gap layer exceeds an average concentration found by the Hall method by more than 2 times. The proposed technique was used for determining the temperature dependences of the insulator capacitance, capacitance and differential resistance of the space-charge region, and capacitance of the inversion layer in MIS structures based on n-Hg0.775Cd0.225Te without a graded-gap layer. The temperature and voltage dependences of the parameters of the equivalent circuit elements in strong inversion are calculated. The results of calculation are qualitatively consistent with the results obtained from the measurements of the admittance

Electro-physical characteristics of MIS structures with HgTe-based single quantum wells

The paper presents brief research results of the admittance of metal-insulator- semiconductor (MIS) structures based on Hg1-xCdxTe grown by molecular-beam epitaxy (MBE) method including single HgCdTe/HgTe/HgCdTe quantum wells (QW) in the surface layer. The thickness of a quantum well was 5.6 nm, and the composition of barrier layers with the thickness of 35 nm was close to 0.65. Measurements were conducted in the range of temperatures from 8 to 200 K. It is shown that for structure with quantum well based on HgTe capacitance and conductance oscillations in the strong inversion are observed. Also it is assumed these oscillations are related with the recharging of quantum levels in HgTe

Some properties of near-surface layer of graded-gap MBE HgCdTe after boron ion implantation

The effect of ion implantation of boron ions with an energy of 100 keV and a dose of (1-6)×1015 cm-2 in the MBE HgCdTe films on the characteristics of the MIS structures based on these films was investigated. The changes of the conductivity type in the near-surface layer of HgCdTe after ion implantation of boron and etching by ions of argon were detected. The concentrations of the major charge carriers in the near-surface layer of the epitaxial films after ion implantation and after ion etching were close to 5.88×1016 cm-3 and 2.47×1017 cm-3, respectively

Electro-physical characteristics of MIS structures with HgTe-based single quantum wells for optoelectronics devices

The paper presents brief research results of the admittance of metal-insulator- semiconductor (MIS) structures based on Hg1-xCdxTe grown by molecular-beam epitaxy (MBE) method including single HgCdTe/HgTe/HgCdTe quantum wells (QW) in the surface layer. The thickness of a quantum well was 5.6 nm, and the composition of barrier layers with the thickness of 35 nm was close to 0.65. Measurements were conducted in the range of temperatures from 8 to 200 K. It is shown that for structure with quantum well based on HgTe capacitance and conductance oscillations in the strong inversion are observed. Also it is assumed these oscillations are related with the recharging of quantum levels in HgTe

Temperature dependence of the absorption edge of synthetic diamond

Using optical spectroscopy in the spectral range from 200 to 300 nm, the absorption edge and transmission spectra of 7 samples of synthetic diamond of IIa type in the temperature range from 12 K to 470 K was studied. Using numerical methods, the temperature dependences of optical absorption into the free exciton state were obtained for negative and positive phonon branches

Photoluminescence and optical absorption of diamond samples containing NV centers

NV center is an impurity defective complex in diamond, obtained by irradiating with highenergy electrons samples containing nitrogen in a substituting position and post radiating annealing. NV centers are observed in several charge states negative (zero phonon line at 638 nm), neutral (ZPL at 575 nm), and, possibly, positive (ZPL at 533 nm). NV centers in diamond are candidates for qubits for quantum computing, the basis of high speed magnetometric sensors, sources of single photons, and also emitting centers of optically active laser media

Influence of infrared radiation on the electrical characteristics of the surface-barrier nanostructures based on MBE HgCdTe

Impact of illumination on the admittance of the MIS structures based on MBE Hg1-xCdxTe with graded-gap layers and single quantum wells was investigated. It is shown that for HgCdTe-based nanostructures the illumination greatly affects the capacitance and conductance dependencies. The capacitance-voltage characteristics exhibit a low-frequency behavior, which is associated with a decrease in the differential resistance of the space charge region. Especially informative illumination exposure is in the study of deep traps in n-HgCdTe (x=0.21-0.23) without graded-gap layer. Illumination leads to the low-frequency behavior of capacitance-voltage characteristics of MIS structures based on p-HgCdTe with HgTe single quantum well in the active region, and maximums in the voltage dependences do not appear