Single Heterojunction barrier at terahertz frequency

Single hetcrostmcture barrier is a substantial part of a wide spectrum of twoand three-terminal devices. The mechanisms of current flow across the barrier are very important from the paint of view of electronic device physics. Depending on a layer composition, materials, doping profiles and external electric field electrons and holes in such structures participate in different emission and tunneling processes. The heterastructure barrier can act as a simple electron emitter especially in different hat electron devices [2]; for this purpose the barrier should be transparent. Another structure is the single heterojunction barrier varactor diode (HBV) that has received considerable attention as a promising device for high frequency multiplication in the milimeter to submilimeter wavelength range. The device consists of a large bandgap semiconductor sandwiched between symmetric moderately doped modulation regions of a smaller bandgap material [4], [6]. Although the investigation of high frequency effects is of great importance for electronics, papers concerning high-frequency phenomena are usually devoted to the resonant tunnelling diodes [I], [3] and different types of potential barriers are rarely investigated.