J. P. Banerjee

Bio: J. P. Banerjee is an academic researcher from University of Calcutta. The author has contributed to research in topics: Space charge & Electronic band structure. The author has an hindex of 3, co-authored 3 publications receiving 39 citations.

The electronic contribution to the elastic constants in ultrathin films of ternary and quaternary alloys in the presence of an arbitrarily oriented magnetic field: Theory and suggestion for experimental determination

Abstract: An attempt is made to study the electronic contribution to the elastic constants in ultrathin films of ternary and quaternary alloys in the presence of an arbitrarily oriented magnetic field on the basis of a new electron dispersion law. It is found, taking and lattice matched to InP as examples of ternary and quaternary alloys, that the said contribution increases with increasing surface electron concentration and the band non-parabolicity enhances its magnitude. They decrease with increasing film thickness and alloy composition in various oscillatory manners. Moreover, the numerical values of the contributions in ternary materials are greater than those in quaternary compounds. An experimental method is suggested for determining the electronic contribution to the elastic constants in degenerate compounds having arbitrary dispersion laws. In addition, the well known results for wide-band-gap ultrathin materials in the absence of a magnetic field have been obtained as special cases of our generalized formulations under certain limiting conditions.

The carrier contribution to the elastic constants in small-gap materials

Abstract: We present a simple theoretical analysis of the carrier contribution to the second and third order elastic constants in nonparabolic materials on the basis of an electron dispersion law by taking into account various anisotropies of the energy band structure within the framework of k⋅p formalism. It is found that the carrier contributions to the elastic constants in n-Cd3As2, InSb, InAs, GaAs, Hg1−xCdxTe, and lattice matched In1−xGaxAsyP1−y increase with the increase of carrier degeneracy in different manners which, depend on the material parameters and band structure. A relationship between the said contributions and the thermoelectric power has been derived for materials obeying arbitrary dispersion laws in the presence of a classically large magnetic field. Our analysis is based on the derivation of a more generalized band structure of the materials which agrees well with the relationship suggested. It is also observed that the second and third order elastic constants increase with the decrease of allo...

Computer studies of quasi Read gallium arsenide IMPATT diode : including the effect of space charge

Abstract: Computer studies have been carried out on the effects of variation of impurity hump parameters of quasi Read high–low (hi–lo) and low–high–low (lo-hi–lo) gallum arsenide IMPATT diodes on their DC and microwave properties. The effect of mobile space charge has been included in the computer analysis. It turns out that the DC properties of the diode are sensitive functions of the width and doping concentration of impurity bumps. The optimum efficiency is found to be respectively 24.5% and 27.9% for hi–lo and lo-hi–lo diodes designed for 18 GHz frequency. The small signal admittance calculations show that a lo-hi–lo structure provides higher negative conductance and better quality factor compared with a hi–lo structure of GaAs Impatt diode.

A simple theoretical analysis of the effective electron mass in III-V, ternary and quaternary materials in the presence of light waves

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

Simple theory of the optical absorption coefficient in nonparabolic semiconductors

Abstract: A simple theory is developed of the optical absorption coefficient (OAC) in nonparabolic semiconductors on the basis of the three-band model of Kane, by considering the wave-vector (k) dependence of the optical matrix element. It has been found that the OAC is proportional to [(ℏω)2−Eg2]1/2 (ℏω and Eg are the energy of the incident radiation and the bandgap, respectively) instead of [(ℏω)−Eg]1/2, the conventional form. It has been demonstrated, by taking n-InAs, n-InSb, Hg1−xCdxTe, and In1−xGaxAs1−yP1−y lattice matched to InP as examples, that the OAC increases with increasing photon energy and the value of the same coefficient in the three band model of Kane is greater than that in parabolic energy bands in all the cases. The well-known result for wide gap materials having parabolic energy bands has also been obtained from our generalized formulation under certain limiting condition.