Low field mobility in electrostatically evolved AlGaN/GaN one-dimensional channel from a two-dimensional electron gas system

摘要

Here, we have investigated size dependent electron mobility in an electrostatically evolved AlGaN/GaN one-dimensional channel from a two-dimensional heterostructure. An architecture with lateral gates, which allows partial depletion of channel widths, has been used. The low field mobility is found to manifest multiple peaks and valleys for progressively changing quantum confinement. The number of sub-bands increases with the increasing dimension. However, electron and phonon confinement decrease, which leads to less wave-function overlap. Although an increase in the number of sub-bands decreases the mobility due to the larger number of density of states, the overlap decreases monotonically which increases the mobility. The two competing effects lead to a unique signature on the mobility. The depletion region voltage exponent is found to differ from the traditional value of 0.5 in this case. The exponent is found to be close to unity for a one-dimensional system.