Nanotechnology

Wide-bandgap semiconductor

Materials science

Ultraviolet

Photodetector

Gallium nitride

Layer (electronics)

Optoelectronics

Nanowire

Nano Letters

We present a study of GaN single-nanowire ultraviolet photodetectors with an embedded GaN/AlN superlattice. The heterostructure dimensions and doping profile were designed in such a way that the application of positive or negative bias leads to an enhancement of the collection of photogenerated carriers from the GaN/AlN superlattice or from the GaN base, respectively, as confirmed by electron beam-induced current measurements. The devices display enhanced response in the ultraviolet A ($\approx$ 330-360 nm) / B ($\approx$ 280-330 nm) spectral windows under positive/negative bias. The result is explained by correlation of the photocurrent measurements with scanning transmission electron microscopy observations of the same single nanowire, and semi-classical simulations of the strain and band structure in one and three dimensions.

Bias-Controlled Spectral Response in GaN/AlN Single-Nanowire Ultraviolet Photodetectors