Min Gong

Influence of the Heterojunction Spacer on the Performance of AlGaN/GaN/AlGaN Resonant Tunneling Diodes

We report on a simulation for an aluminum gallium nitride (AlGaN)/gallium nitride (GaN) resonant tunneling diode (RTD) with a step heterojunction emitter spacer (SHES) at room temperature. An SHES and low Al component barriers were introduced in to AlGaN/GaN RTDs to improve the electronic injection efficiency in to the emitter, reduce the transit time in the collector depletion region, and achieve lattice matching. The substitution of the emitter spacer for the SHES alters the dominant transport mechanism, increases the tunneling current, and restrains the thermionic current. As a result, the peak current was 1.683 A at 0.39 V and the peak-to-valley current difference was 0.93 A.

Modeling and optimization of a double-well double-barrier GaN/AlGaN/GaN/AlGaN resonant tunneling diode

The influence of a GaN layer as a sub-quantum well for an AlGaN/GaN/AlGaN double barrier resonant tunneling diode (RTD) on device performance has been investigated by means of numerical simulation. The introduction of the GaN layer as the sub-quantum well turns the dominant transport mechanism of RTD from the 3D-2D model to the 2D-2D model and increases the energy difference between tunneling energy levels. It can also lower the effective height of the emitter barrier. Consequently, the peak current and peak-to-valley current difference of RTD have been increased. The optimal GaN sub-quantum well parameters are found through analyzing the electrical performance, energy band, and transmission coefficient of RTD with different widths and depths of the GaN sub-quantum well. The most pronounced electrical parameters, a peak current density of 5800u2009KA/cm2, a peak-to-valley current difference of 1.466u2009A, and a peak-to-valley current ratio of 6.35, could be achieved by designing RTD with the active region struct...

Compared current-voltage characteristics of silicon and cubic silicon caibine pn-junction based on the silicon substrate

Cubic silicon carbide pn junction was synthesized on Silicon substrate by Low pressure chemical vapor deposition. The methane diluted with Hydrogen was used as the reaction carbon source, while silicon substrate was used as the silicon source. The cubic silicon carbide films were characterized by X-ray diffraction, high resolution transmission electron microscopy and current-voltage. It is found that the threshold voltage of cubic silicon carbide is bigger than Si pn junction and the electronic characteristics of cubic silicon carbide pn junction is quite insensitive to ultraviolet light.