Voicu Dolocan

Effects of Spatial Dependence of Recombination Centers on the I‐V Characteristics of p‐n Junctions

Effects of spatial dependence of recombination centers on the I‐V characteristics of p‐n junctions are calculated. The results obtained show that these effects may explain the experimental deviations from the Shockley p‐n junction theory and from the theory of the carrier generation‐recombination in the space‐charge region. The most important result for applications is the junction in which the lifetime increases in the direction of the carrier diffusion; in this case for diffusion current, at reverse bias, a negative resistance appears.

A NEW HAMILTONIAN OF INTERACTION FOR FERMIONS

Using the Lagrangian formalism we attempt to introduce a new Hamiltonian for fermions. On this basis we have evaluated the expectation values for the interaction energy between fermions via bosons. The interaction energy between two fermions via phonons becomes attractive in a degenerate fermion-gas. The interaction energy between two fermions via photons appears to be attractive in certain conditions. The self-energy of the fermion + boson system, e.g. polaron and polariton, was evaluated.

QUANTUM MECHANICAL TREATMENT OF THE ELECTRON{BOSON INTERACTION VIEWED AS A COUPLING THROUGH FLUX LINES. POLARONS

By using a Hamiltonian based on the coupling through flux lines between electrons and bosons, we have calculated the electron–phonon interaction energy and the electron–electron interaction energy via bosons in an isotropic medium and in a lattice. We have calculated the correction energy to the electron energy due to the electron interaction with acoustic phonons and we have found that in covalent crystals it is of the order of 0.1 eV. Also, we have presented the results for the weak coupling and strong coupling polarons in ionic crystals. By applying this Hamiltonian to electron–electron interaction via mass less bosons we have found an equivalent expression for Coulombs law, αℏc/R, where α is the fine structure constant.

APPLICATIONS OF A NEW HAMILTONIAN OF INTERACTION TO ONE-DIMENSIONAL AND TWO-DIMENSIONAL STRUCTURES

We apply a new interaction Hamiltonian (Ref. 1) to two-dimensional and one-dimensional structures. We have found that, for small values of the wavevector, the interaction energy presents a logarithmic divergence and in a one-dimensional lattice, a cotangent divergence in addition. But, in a two-dimensional lattice the divergence terms may cancel, and from the point of view of the interactions the crystal structure is possible. The interaction energy has a polynomial dependence on the form 1/an where the maximum value of n is 7; a is the lattice constant.

On the p—n junctions in the electric and magnetic fields†

The p-n junction in the electric and magnetic fields is studied. The results obtained show that the magnetosensitivity of the high-level current is greater than the magneto-sensitivity of the low-level current. The influence of the electric field of the neutral regions on the I—V characteristics of p—n junctions is discussed.

On the carrier generation-recombination in the space-charge region of a p-n junction†

Abstract In this paper the gradual capture effect on the goneration-recombination current in the space-charge region for an asymmetrical junction is studied. The theory ia applied to the p+-n InSb diodes. At forward bias, when the lifetime increases in the direction from p+ region to n region, the results we have obtained show that the current increases more rapidly ivith voltage than in the reverse case.

On the p-n junctions at variable signals†

Abstract The role of gradual capture in p-n junctions and transistors at a.c. voltage was studied. The results obtained show that the diffusion capacity of the p-n junction in the case where the carrier lifetime increases in the direction of the carrier diffusion is greater than in the reverse case. But for p-n junction resistance a reverse situation occurs.

RELATION OF INTER-ATOMIC FORCES IN SOLIDS TO BULK MODULUS, COHESIVE ENERGY AND THERMAL EXPANSION

We present theoretical expressions relating the cohesive energy to the bulk modulus, the force constant and the lattice constant applicable to solids with a variety of crystal structures. We have found that the cohesive energy is directly proportional to the ratio between the product of the bulk modulus through the atomic volume and the exponent of the repulsion term. We have defined a figure of merit for materials as the ratio between the product of the bulk modulus through the atomic volume and the cohesive energy. The reciprocal of this ratio is a measure of the hardness of materials. Likewise, we have found the expressions for anharmonicity and thermal expansion coefficients, which can explain, also, their possible negative values.

APPLICATION OF A NEW HAMILTONIAN OF INTERACTION TO VORTICES STRUCTURE IN SUPERCONDUCTORS

By using a new Hamiltonian,1 we have calculated the energy of one isolated vortex line and also the interaction energy between the vortices in superconductors. Also, we have calculated the elastic force constant in a vortex lattice. The interaction energy shows a minimum at a certain distance between the vortices. We analyze some aspects of this interaction. The obtained results are in good agreement with experimental data.

Elastic Coupling Through Flux Lines and Magnetic Interaction

We show that elastic coupling through flux lines gives an interaction energy between two superconductors or magnetic pieces, which is inversely proportional to the distance between the two bodies. First, we present some details on the penetration depth of the magnetic field in layered superconductors and, especially, on the vortex lines.