Control on Electron Tunnelling by Fine Band Engineering upon Semiconductor Potential Barriers
Quantum tunnelling (QTN) devices show a promising future for energy saving and ultrafast operating thanks to the unprecedented development of two-dimensional materials. However, the immature techniques for device fabrication hamper severely their further progress and application. To overcome such a challenge, the abundant processing technology used in semiconductor electronics is worth resorting to. Herein, a device prototype is fabricated based on band engineering to enable flexible control on QTN probability (TP) within an III-V semiconductor multilayer. While the initial heights of all barriers are set to obtain similar TP under no bias, the conduction band slopes of InGaSb and AlSb barriers are modulated to a state where their TP varies reversely under electric fields. On that basis, revealed by in-situ bias electron holography, a unidirectional accumulation of electrons has been realized inside the multilayer structure. Moreover, the inevitable element segregation/diffusion during device growth play a key role in band structure optimization, which is confirmed by strain analysis. The feasibility of the above modulation strategy is also confirmed by theoretical simulations. Our findings might provide a new perspective on the innovation of semiconductor devices and the application of QTN effect.