Evaluation of the Conduction Band Discontinuity of MgSe/ZnCdSe Heterojunctions on InP Substrates Using n–i–n Diodes

Conduction band discontinuity (ΔEc) of MgSe/ZnCdSe heterojunctions were evaluated using n–i–n diodes consisting of an undoped i-MgSe layer sandwiched by n-doped ZnCdSe layers. The n–i–n diodes were fabricated on InP substrates by molecular beam epitaxy. Injection current density versus applied voltage (J–V) characteristics of the n–i–n diodes were measured at 77 K and room temperature. In addition, the theoretical J–V characteristics of the n–i–n diode were calculated while varying ΔEc. By fitting the theoretical data to the experimental data, ΔEc was estimated to be 1.2 eV from the result at 77 K. This value is similar to the ΔEc estimated from the literature.