Flexible AlGaInN/GaN Heterostructures for High-Hole-Mobility Transistors

We study the potential and feasibility of high hole mobility transistors (HHMTs) based on flexible AlGaInN/GaN heterostructures using numerical simulation. We develop a map for the sheet density of two-dimensional hole gas (2DHG) at different mole fractions of AlN, GaN, and InN of AlGaInN with mechanical bending conditions. External compressive strain via bending can induce relatively high density of 2DHG (e.g., > 8×10
¹²
cm
^-2
) while keeping InN fraction low (<;0.3) so that 2DHG channel can be formed in a GaN layer. We show the electronic energy band diagrams, family curves of I - V characteristics, and transfer characteristics of an In
_0.25
Al
_0.75
N/GaN heterostructure in different bending conditions. By bending up, 2DHG is formed to perform the device function as HHMTs. Without bending, 2-D electron gas is induced and the devices function as high electron mobility transistors. This unique property can be used in complementary integrated circuits for high-power and high-temperature applications.