GaN and InGaN(112_2) surfaces: group-III adlayers and indium incorporation

Abstract

As printed transistor and sensor technologies advance, their integration into complex electronic systems becomes possible. Electronic design of such systems requires a systematic approach to simulation and design that takes into account the distinct challenges and opportunities presented by printed devices. In this talk, the speaker will discuss PARC’s approach to circuit design and modeling in the context of building sensor systems in partnership with Thinfilm Electronics based on an ink-jet printed organic TFT process. First-principles calculations of total energy performed for clean and In-rich GaN(112_2) surfaces indicate that indium will, for the same chemical potential, incorporate in higher concentrations on the (112_2) surface than on the (101_0) surface. Because an In atom is larger than the Ga atom it replaces there is an effective repulsive interaction between incorporated In atoms on the surface. On the In-rich (112_2) surface the repulsive interaction is much weaker than it is on the (101_0) surface. For this reason the concentration of indium atoms incorporated in growth on the (112_2) surface can exceed the concentration obtained on the (101_0) surface.