Characteristics of a Zn0.7Mg0.3O/ZnO heterostructure field-effect transistor grown on sapphire substrate by molecular-beam epitaxy -: art. no. 112106

Characterization of a Zn0.7Mg0.3O/ZnO heterostructure field-effect transistor (HFET) is reported. The HFET was based on a Zn0.7Mg0.3O/ZnO/Zn0.7Mg0.3O single quantum well (SQW) grown on an a-plane sapphire substrate by molecular-beam epitaxy, and was fabricated by a conventional photolithography technique combined with dry etching. Room-temperature characteristic of the HFET was a n-channel depletion type with a transconductance of 0.70 mS/mm and a field-effect mobility of 140 cm(2)/V s, in good agreement with the electron Hall mobility in SQW of 130 cm(2)/V s. The on/off ratio at V-DS=3 V was similar to 800, which was limited by an insufficiently suppressed leakage current through the bottom Zn0.7Mg0.3O barrier. (c) 2005 American Institute of Physics.