Field-emission pumping of a ZnSe/CdSe/ZnSe nanoheterostructure with low-energy electrons through a surface potential barrier

A planar MIS structure with a MgSe dielectric barrier has been studied. Hot electrons were injected into the wide-bandgap ZnSe/CdSe/ZnSe nanoheterostructure by field electron emission from a metallic electrode. The average parameters of the potential barrier at the metal-insulator interface were determined. It was found experimentally that the area across which the emission current flows is substantially smaller than the area of the metallic electrode. This may be due to “crowding” of the current flowing across a thin heterogeneous layer of the insulator. It was shown that, to make the characteristics of the MIS structure more stable, it is necessary to create a high-quality homogeneous potential barrier. The estimated maximum local density of the emission current, $I_{\mathrm{max}}\cong 10^3$ A/cm$^2$, is sufficient for satisfying the lasing conditions in the heterostructure. Therefore, the suggested pumping method can be used to develop lasers based on wide-bandgap semiconductor heterostructures without $p$–$n$ junctions.