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EN
The dielectric response of gallium doped Cd_{0.99}Mn_{0.01}Te and CdTe alloys possessing DX centers was studied by impedance spectroscopy. Complex modulus and impedance spectroscopic plots were analyzed. Near ideal Debye response of CdTe:Ga was observed, whereas for Cd_{0.99}Mn_{0.01}Te:Ga samples non-Debye behavior was stated. Different relaxation responses may be related to various local atomic configurations in the vicinity of the DX centers in the studied materials.
EN
Deep electron states in gallium doped CdTe have been studied by deep-level transient spectroscopy method. The Schottky Au-CdTe diodes were processed to perform the investigations. Rectifying properties of diodes have been examined by the room temperature current-voltage and capacitance-voltage measurements. Deep-level transient spectroscopy measurements performed in the range of temperatures 77-350 K yield the presence of three electron traps. The thermal activation energies and apparent capture cross-sections have been determined from related Arrhenius plots. The dominant trap of activation energy E_2 = 0.33 eV and capture cross-section σ_2 = 3 × 10^{-15} cm^2 has been assigned to the gallium related DX center present in the CdTe material.
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Impedance Spectroscopy of Au-CdTe:Ga Schottky Contacts

88%
EN
The dielectric response of Au-CdTe gallium doped Schottky contacts was investigated by impedance spectroscopy in the frequency range from 0.2 Hz to 3 MHz, at temperatures in the range from 77 K to 300 K. Combined modulus and impedance spectroscopic plots were analyzed to study the response of the structure. The data were fitted with the simple RC circuit composed of a depletion layer capacitance in parallel with resistance and a series resistance of the bulk CdTe:Ga. The activation energy of the bulk trap obtained from the Arrhenius plot of the resistance was found to be equal to 0.08 eV, close to the value 0.09 eV obtained from the impedance-modulus spectroscopy. The trap dominant in CdTe:Ga is possibly the DX center related, as it has been observed that this is the dominant trap in the material.
EN
p^+-n GaN diodes were studied by means of conventional deep level transient spectroscopy and Laplace transform deep-level spectroscopy methods within the temperature range of 77-350 K. Deep level transient signal spectra revealed the presence of a majority and minority trap of indistinguishable signatures. The Laplace transform deep-level spectroscopy technique due to its superior resolution allows us to unambiguously identify and characterize the traps. The apparent activation energy and capture cross-section for the majority trap were found to be equal to 0.63 eV and 2 × 10^{-16} cm^2 and for the minority trap 0.66 eV and 1.6 × 10^{-15} cm^2. It has been confirmed that the Laplace transform deep-level spectroscopy technique is a powerful tool in characterization of the traps of close signatures.
EN
In this paper the electronic states of self-organized CdTe quantum dots embedded in ZnTe matrix are studied by means of capacitance-voltage (C-V) characteristics within the temperature range of 180-300 K. A reference diode of the same layer structure but without quantum dots is studied also for comparison. The C-V characteristics measured for the reference diode exhibit bulk behaviour in contrast to the quantum dots sample for which a characteristic step corresponding to discharging of quantum dots is clearly visible within broad range of temperatures. A quasistatic model based on the self-consistent solution of the Poisson equations is used to simulate the capacitance. By comparison the calculated C-V curve with experimental curve the apparent thermal activation energy for hole emission from the quantum dots to the ZnTe matrix is found to be equal to (0.12 ± 0.03) eV.
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Hole Traps in ZnTe with CdTe Quantum Dots

76%
EN
In this study the capacitance-voltage (C-V) and deep level transient spectroscopy measurements have been performed on ZnTe (p-type)-Ti/Al Schottky diodes containing a layer of CdTe self-assembled quantum dots and on the reference diodes without dots for comparison. Both kinds of investigated samples were grown by molecular beam epitaxy technique. The dots were formed during the Stransky-Krastanov growth mode. Comparison of the C-V and deep level transient spectroscopy results obtained for both samples allows us to conclude that the 0.26 eV trap observed exclusively for the QD sample can be assigned to some defects in a wetting layer or CdTe/ZnTe interface.
8
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Deep Levels Induced by CdTe/ZnTe Quantum Dots

64%
EN
The electrical properties of the CdTe/ZnTe quantum dot system have been analyzed to identify deep-level defects related with the presence of quantum dots. The capacitance-voltage (C-V) and deep level transient spectroscopy measurements were used to investigate the samples. A reference ZnTe sample (without dots) was also studied for comparison. Both samples were grown by molecular beam epitaxy technique on the n-type GaAs substrate. The quantum dots were formed by a Zn-induced reorganization of a thin CdTe layer. The presence of quantum dot formation was confirmed by micro-photoluminescence measurements. The deep level transient spectra for both samples are complex. In order to characterize individual contributions to the deep level transient spectra the latter have been simulated by separated Gaussian components [1]. The results of the deep level transient spectroscopy measurements yield the conclusion that the same defects are present in both materials but there is an increased concentration of the defects in the quantum dot structures. No deep level associated directly with the quantum dot confinement has been identified.
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