Traditional X-ray detectors use bulk crystals, which limits their resolution. In this project, financed by an ERC Starting Grant, we are developing vertical arrays of nanowires as high-resolution X-ray detectors. We have shown that X-rays can be detected by single nanowires, with much higher spatial resolution than commercial systems [Chayanun 2020].

X-rays that are absorbed in a semiconductor excite electrons over the bandgap, and in the presence of an internal or external electric field the electrons will generate a measurable current. With a nanofocused X-ray beam, we can locally probe the electronic properties of semiconductor devices. We have shown that X-rays can be used to image the carrier collection within single nanowire solar cells [Chayanun 2019].  We also demonstrated that scanning X-ray fluorescence can be used for mapping Zn dopants in InP nanowires with 50 nm resolution [Troian 2018].