Semiconducting M_(2)X(M=Cu,Ag,Au;X=S,Se,Te)monolayers:A broad range of band gaps and high carrier mobilities

Two-dimensional semiconductors(2DSCs)with appropriate band gaps and high mobilities are highly desired for future-generation electronic and optoelectronic applications.Here,using first-principles calculations,we report a novel class of 2DSCs,group-11-chalcogenide monolayers(M_(2)X,M=Cu,Ag,Au;X=S,Se,Te),featuring with a broad range of energy band gaps and high carrier mobilities.Their energy band gaps extend from 0.49 to 3.76 eV at a hybrid density functional level,covering from ultraviolet-A,visible light to near-infrared region,which are crucial for broadband photoresponse.Significantly,the calculated room-temperature carrier mobilities of the M_(2)X monolayers are as high as thousands of cm^(2)·V^(-1)·s^(-1).Particularly,the carrier mobilities ofε-Au_(2)Se and e-Au2Te are up to 104 cm^(2)·V^(-1)·s^(-1),which is very attracitive for electronic devices.Benefitting from the broad range of energy band gaps and superior carrier mobilities,the group-11-chalcogenide M_(2)X monolayers are promising candidates for future-generation nanoelectronics and optoelectronics.