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S. N. Biswas

Bio: S. N. Biswas is an academic researcher. The author has contributed to research in topics: Electric field & Ternary operation. The author has an hindex of 2, co-authored 2 publications receiving 41 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, an attempt is made to investigate the thermoelectric power of the electrons under strong magnetic quantization in n-channel inversion layers of ternary chalcopyrite semiconductors at low temperatures, taking n−channel inversions layers on CdGeAs2 as examples, under both the weak and strong electric field limits, respectively.
Abstract: An attempt is made to investigate the thermoelectric power of the electrons under strong magnetic quantization in n‐channel inversion layers of ternary chalcopyrite semiconductors at low temperatures, taking n‐channel inversion layers on CdGeAs2 as examples, under both the weak and strong electric field limits, respectively. We have formulated the magneto‐thermo power on the basis of newly derived two‐dimensional electron energy spectra for both the limits by considering various types of anisotropies of the band parameters within the frame work of k■p formalism. It has been observed that, the magneto‐thermo power decreases with increasing surface electric field and decreasing quantizing magnetic field in an oscillatory manner for both the limits. The crystal field parameter enhances the numerical magnitudes and the corresponding results for n‐channel inversion layers of parabolic semiconductors have also been obtained as special cases from the generalized expressions under certain limiting conditions.

28 citations

Journal ArticleDOI
TL;DR: In this article, the gate capacitance of n-channel inversion layers on ternary chalcopyrite semiconductors at low temperatures was derived under both weak and strong electric field limits.
Abstract: An attempt is made to derive model expressions of the gate capacitance of metal–oxide semiconductor structures in n‐channel inversion layers on ternary chalcopyrite semiconductors at low temperatures, taking n‐channel inversion layers on CdGeAs2 as examples, under both the weak and strong electric field limits, respectively. It is found, on the basis of newly derived two‐dimensional electron energy spectra within the frame work of k↘⋅p↘ formalism for both the limits by considering the anisotropies of the band parameters, that the gate capacitances increase with increasing surface electric field in an oscillatory manner and the crystal‐field splitting parameter enhances the numerical values of the gate capacitance for both the limits. In addition, the corresponding well‐known results for n‐channel inversion layers on parabolic energy bands are also obtained from the generalized expressions.

20 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, an attempt is made to investigate the thermoelectric power of the electrons under strong magnetic quantization in n-channel inversion layers of ternary chalcopyrite semiconductors at low temperatures, taking n−channel inversions layers on CdGeAs2 as examples, under both the weak and strong electric field limits, respectively.
Abstract: An attempt is made to investigate the thermoelectric power of the electrons under strong magnetic quantization in n‐channel inversion layers of ternary chalcopyrite semiconductors at low temperatures, taking n‐channel inversion layers on CdGeAs2 as examples, under both the weak and strong electric field limits, respectively. We have formulated the magneto‐thermo power on the basis of newly derived two‐dimensional electron energy spectra for both the limits by considering various types of anisotropies of the band parameters within the frame work of k■p formalism. It has been observed that, the magneto‐thermo power decreases with increasing surface electric field and decreasing quantizing magnetic field in an oscillatory manner for both the limits. The crystal field parameter enhances the numerical magnitudes and the corresponding results for n‐channel inversion layers of parabolic semiconductors have also been obtained as special cases from the generalized expressions under certain limiting conditions.

28 citations

Book ChapterDOI
TL;DR: In this article, the structure, magnetic, and related properties of the ThMn12-type compounds of rare earths and actinides are presented, and the magnetic coupling for these compounds is determined only for the AnFe4Al8 seiles in neutron diffraction (ND) experiment.
Abstract: Publisher Summary This chapter presents the structure, magnetic, and related properties of the ThMn12-type compounds of rare earths and actinides. There are two distinct subgroups in this family of compounds: (1) those with a relatively low content of transition element and (2) those with a high concentration of the iron-group elements, mostly Fe, Co, and Ni. For the first subgroup, the transition elements belong to the iron group except for Co and Ni and the most popular stabilizing element is Al; however, Ga can also be used as a stabilizing component. For the second subgroup, Si, Ti, V, Cr, Mn, Mo, and Re are most frequently found as the stabilizing component for the rare-earth compounds, whereas only compounds with Si, and exceptionally with Mo and Re, are formed by uranium. The magnetic coupling for the ThMn12-type compounds is determined only for the AnFe4Al8 seiles in neutron diffraction (ND) experiment. Neutron investigations have been performed for other compounds as well, although for these either the transition-metal sublattice or both the actinide and transition-metal sublattices are nonmagnetic.

26 citations

Journal ArticleDOI
TL;DR: In this article, a simple theoretical analysis of the effective electron mass (EEM) at the Fermi level for III-V, ternary and quaternary materials, on the basis of a newly formulated electron energy spectra in the presence of light waves whose unperturbed energy band structures are defined by the three-band model of Kane, is presented.
Abstract: We present a simple theoretical analysis of the effective electron mass (EEM) at the Fermi level for III–V, ternary and quaternary materials, on the basis of a newly formulated electron energy spectra in the presence of light waves whose unperturbed energy band structures are defined by the three-band model of Kane The solution of the Boltzmann transport equation on the basis of this newly formulated electron dispersion law will introduce new physical ideas and experimental findings under different external conditions It has been observed that the unperturbed isotropic energy spectrum in the presence of light changes into an anisotropic dispersion relation with the energy-dependent mass anisotropy In the presence of light, the conduction band moves vertically upward and the band gap increases with the intensity and colours of light It has been found, taking n-InAs, n-InSb, n-Hg1−xCdxTe and n-In1−xGaxAsyP1−y lattice matched to InP as examples, that the EEM increases with increasing electron concentration, intensity and wavelength in various manners The strong dependence of the effective momentum mass (EMM) at the Fermi level on both the light intensity and wavelength reflects the direct signature of the light waves which is in contrast with the corresponding bulk specimens of the said materials in the absence of photo-excitation The rate of change is totally band-structure-dependent and is influenced by the presence of the different energy band constants The well known result for the EEM at the Fermi level for degenerate wide gap materials in the absence of light waves has been obtained as a special case of the present analysis under certain limiting conditions, and this compatibility is the indirect test of our generalized formalism

23 citations

Journal ArticleDOI
TL;DR: In this paper, the thermoelectric power in the presence of a large magnetic field (TPM) in heavily doped III-V, II-VI, PbTe/PbSnTe, strained layer and HgTe/CdTe quantum dot superlattices (QDSLs) with graded structures was analyzed.
Abstract: We study theoretically the thermoelectric power in the presence of a large magnetic field (TPM) in heavily doped III–V, II–VI, PbTe/PbSnTe, strained layer and HgTe/CdTe quantum dot superlattices (QDSLs) with graded structures on the basis of newly formulated electron energy spectra and compare the same with that of the constituent materials. It has been found, taking heavily doped GaAs/Ga1−xAlxAs, CdS/CdTe, PbTe/PbSnTe, InAs/GaSb and HgTe/CdTe QDSLs as examples, that the TPM increases with increasing inverse electron concentration and film thickness, respectively, in different oscillatory manners and the nature of oscillations is totally band structure dependent. We have also suggested the experimental methods of determining the Einstein relation for the diffusivity–mobility ratio, the Debye screening length and the electronic contribution to the elastic constants for materials having arbitrary dispersion laws.

23 citations

Journal ArticleDOI
TL;DR: In this paper, a simple theoretical analysis of the thermoelectric power under strong magnetic quantization (TPM) in III-V, II-VI, PbTe/PbSnTe, strained layer and HgTe/CdTe superlattices (SLs) with graded interfaces was presented.
Abstract: An attempt is made in this paper to present a simple theoretical analysis of the thermoelectric power under strong magnetic quantization (TPM) in III–V, II–VI, PbTe/PbSnTe, strained layer and HgTe/CdTe superlattices (SLs) with graded interfaces and compare the same with that of the constituent materials by formulating the respective magneto dispersion laws, which in turn control all the transport properties through Bolzmann transport equation. It has been observed, taking GaAs/Ga 1− x Al x As, CdS/CdTe, PbTe/PbSnTe, InAs/GaSb and HgTe/CdTe with graded interfaces as examples, that the TPM exhibits oscillatory dependence with the inverse quantizing magnetic field due to the SdH and allied SL effects and increases with increasing inverse electron concentration in an oscillatory manner in all the cases. The nature of oscillation is totally band structure dependent and the width of the finite interface enhances the numerical values of the TPM for all the aforementioned SLs. The numerical values of the TPM in graded SLs are greater than that of the constituent materials. The theoretical results are in quantitative agreement with the experimental results as given elsewhere. The well-known expressions for the bulk specimens of wide-gap materials can also be obtained as special cases of our generalized analysis under certain limiting conditions. In addition, we have suggested the experimental methods of determining the Einstein relation for diffusivity–mobility ratio, the Debye screening length and carrier contribution to the elastic constants, respectively, for materials having arbitrary dispersion laws.

19 citations