Electrical Transport and 2DEG Properties Evaluation in InAlN/AlN/ GaN Heterostructures

In0.14 Al0.86N/AlN/GaN heterostructures with different AlN interlayer thicknesses (0-7.5nm) and different barrier layer thicknesses have been investigated by Current-Voltage (I-V) characteristics with Schottky contacts in a planar back-to-back configuration at 300K. Changes in the slope of I-V characteristic have been observed for increasing bias and attributed to the onset of electrical conduction at the AlN/GaN interface, where the two-dimensional electrons gas (2DEG) is located. A new model has been proposed to extract the 2DEG properties from the room temperature I-V measurements. By accurate modelling of the heterostructure and by using the 1-D Schrödinger Poisson solver, the characteristics of the two-dimensional electrons gas (2DEG) forming at the AlN/GaN interface have been calculated. By comparing I-V and Hall Effect results, we assessed the reliability of common I-V analyses in the determination of the major transport properties of the 2DEG. Capacitance-Voltage measurements are under study for further analysis and also to compare the extracted results from proposed model and other methods.