Neutron Transmutation Doping For Phototransistors

Scientists studied the implementation of neutron transmutation doping (NTD) to manipulate electron transfer. NTD is a controllable in-situ substitutional doping method. It utilizes the nuclear reactions of thermal neutrons with the nuclei of the atoms in semiconductors. The process provides a new way to dope 2D materials intentionally without extra reagents. Even after fabrication, it is possible to introduce NTD into any step during the fabrication of 2D-materials-based devices.

Scientists developed NTD in 1975 for bulk semiconductors like Si, gallium phosphide (GaP), and indium phosphide (InP). In 1991, the tin(Sn)-related shallow donors could be uniformly introduced into the bulk indium selenide (InSe) crystal by NTD. The low carrier density of the doped InSe limits the further performance improvement of the 2D layered InSe-based photodetectors. It would be fascinating if 2D layered InSe-based photodetector performances could be manipulated and optimized via the “clean” method of NTD.

The research team realized the doping of 2D layered InSe via NTD for the first time. They successfully narrowed the bandgap and increased the electron mobility of SN-doped layered InSe, reflecting a significant improvement.

Neutron transmutation doping holds enormous promise for the future of materials research. Under the NTD method, dopants can be strictly controlled and introduced at any time, which will improve efficiency.

Read more