In this paper, a strategy to finely modulate the energy band structure to control the carrier confinement capability of digital alloys (DA) is proposed. Strain analysis shows that As and Sb atoms are exchanged within the AlAsSb DA. The bottom of the corrected potential well is low on the left and high on the right in the growth direction, resulting in a higher band offset of the AlSb potential barrier layer on the left side of the potential well than on the right side. The modulation of the band leads to a higher probability of electron tunneling in DA under the action of an electric field opposite to the growth direction. Conversely, it is difficult for the electrons to tunnel into the lower energy level potential wells. TheI-Vcurve of DA shows that the current value under positive bias is significantly smaller than the value under negative bias when the voltage is higher. The measured results correspond perfectly with the modified energy band model, which verifies the feasibility of energy band modulation. This is important for the structural design of DA and the reduction of dark current in optoelectronic devices.
Keywords: atomic exchange; barrier layer; digital alloy; electron tunneling.
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