His topics include the growth of semiconductor thin films, potential barrier with a finite height, density of states, the optical absorption coefficient of the interband transition in quantum wells, the Boltzmann transport equation, hetero-junction field effect transistors, and light-emitting diodes.

Their findings are important because they help understand the influence of the density of states on photovoltaic performance: an increase in the depth and width of the density of states corresponds to an increase in the photocurrent, but also a drop in the open-circuit voltage.

Each chapter presents about 15-20 problems within a text explaining a particular topic, among them inter-atomic forces and lattice vibrations, density of states, thermodynamics of non-interacting quasi-particles, and interactions and phase transitions.

INRXS measures vibrational properties of materials, such as the phonon density of states, and derived quantities like specific heat, vibrational entropy, and the speed of sound.

Appendices address Poisson statistics, parametric amplification, the density of states, low-dimensional semiconductor structures, nuclear magnetic resonance, and Bose-Einstein condensation.

c] is the density of states for the conduction band, [[rho].