A closer look into the III-V semiconductor quantum well under an electric field as used in capacitance- voltage measurement

The total structure of a quantum well (QW), sandwiched in bulk semiconductor with a Schottky barrier on the top and an Ohmic contact at the bottom is a very common and widely used structure in capacitance- voltage (C-V) techniques for band offsets, photo capacitance and deep level transient spectroscopic (DLTS) measurements. In most C-V measurements on quantum wells reported, experimentally determined depth of the QW is much more than the actual depth, of which no proper explanation exists. Also the carrier profile in the well obtained form C-V measurements is not as expected. In this paper we make a consistent and comprehensive study of the mentioned structure under C-V measurements. Poisson's and Schrödinger equations have been solved self consistently to bring out clear pictures of the carrier distribution and energy bands of the total structure at different electric fields. This will lead to an in depth understanding of the widely used experiments and it will help in reducing the discrepancies of experimental C-V measurements on QWs.