Bandgap regulation and doping modification of Ga Cr Se nanosheets.

GaSe, an important direct wide bandgap semiconductor with excellent optoelectronic properties, has wide application potential in the fields of photodetectors, photoelectric sensors and solar cells. Herein, we describe the synthesis of GaSe semiconductor nanoparticles using a high temperature organic liquid phase method. Post-annealing treatment at different temperatures can not only improve the crystallinity of GaSe nanoparticles, but also regulate its optical band gap ranging from 2.50 to 2.80 eV. We further synthesized Ga Cr Se nanosheets by doping CrCl·6HO in the reaction process. By adjusting the Cr doping concentration, Ga Cr Se nanosheets can achieve a continuously tunable band gap in the range of 2.23 eV to 2.42 eV. Both Ga Cr Se nanosheets and GaSe nanoparticles exhibit excellent and stable photoelectric switching performance. With Cr doping, Ga Cr Se exhibits reduced Nyquist impedance and enhanced electrocatalytic activity, which is attributed to its ultrathin nanosheet morphology and large specific surface area. In addition, the diamagnetic behavior of pure GaSe changes to ferromagnetism with different Cr doping concentrations, and its magnetization is as high as 18.0 emu g at = 0.4. These findings demonstrate that Ga Cr Se nanosheets have significant potential in future optoelectronic and magnetoelectric applications.