Electrostatic fields in InGaN/GaN single quantum wells and their variation with indium content, using off-axis holography and energy filtered TEM

摘要

The Ⅲ-Ⅴ nitride system has compounds with the highest piezoelectric coefficients of their class. Using a combination of off-axis electron holography, energy filtered TEM (EFTEM) and high-resolution imaging we have measured the potential difference, indium concentration and width of a set of InGaN/GaN single quantum wells grown over a range of growth temperatures. We have thus measured the electric field strength as a function of indium content and compared this to those field strengths expected both for currently known and theoretically calculated values of the piezoelectric constants.