This study investigates the band bending profile of gallium-nitride-based heterostructures
with respect to the change in the direction of the induced current in the out-of-plane plane
direction, which gives the phase of the terahertz emission peak and can be detected by laser
THz emission microscopy. We use a wavelength-tunable laser THz emission spectroscope
to observe the transport of charges within the band bending regions, excitation of nearby
photocarriers, and carrier scattering. We observe flip-flop peak-to-peak THz emission …