Dependence Of Holes Research Articles

Dependence of hole’s effective mass on the spin polarization and temperature in quantum well

The effective mass of holes (m∗) in GaAs quantum wells is investigated as a function of spin polarization, temperature, and carrier density using the Hartree–Fock approximation. The results reveal m∗ initially decreases at low carrier densities before increasing with density. Additionally, as the interaction parameter increases, m∗ decreases rapidly. Especially, as the temperature rises to 200 K, m∗ asymptotically approaches a value of 0.45m0, where m0 is the electron mass. These findings provide insights into the influence of Coulomb interaction and exchange energy on the effective mass of semiconductors across a wide range of temperatures, spin polarizations, and densities.

Dependence of hole and electron current density of mixed host devices on mixed host composition

The hole and electron current densities of mixed host emitting layer were studied according to the composition of the mixed host to investigate the origin of high quantum efficiency of the mixed host devices. Hole only and electron only devices of mixed host emitting layer were fabricated and the current density of single charge devices was studied. The hole current density was greatly affected by the mixed host composition, while the electron current density was not greatly changed by the mixed host composition. Therefore, the change of hole current density by mixed host composition was critical to the device performances of the mixed host devices.

The Systematics of Irreversibility in Superconducting Thallium Cuprates

ABSTRACTThe irreversibility lines, Hirr(T), for the series of superconducting compoundsTlmA2CunO2+m+2n, where A is Ba or Sr, are measured between 0 and 1 tesla for m = 1,2 and n = 1,2,3 and 4 and show a marked steepening with decreasing anisotropy i.e. as m is lowered from 2 to 1. In addition, for m=2 material Hlrr(T) is observed to steepen with decreasing number of CuO2 layers. The hole dependence of the irreversibility line is also investigated in TI2Ba2CuO6+6 by changing the oxygen stoichiometry, 6. Hirr(T) progressively steepens with increasing hole concentration on the overdoped sida of Tc(max). These results are consistent with a model of flux motion arising from a crossover from 3-D vortex lines to 2-D pancake vortices which are decoupled in the c-direction, and provide guidance for materials selection and optimum doping.

Analytical representations of solid-state devices

Simple expressions for the dependence of hole and electron mobilities upon free carrier densities are utilized to derive equivalent representations of the diode equation as well as other solid-state device equations. The resulting mathematical models vividly display the effects of impurity concentrations in the semiconductor regions on important device parameters.