Cross-sectional scanning tunneling microscopy and spectroscopy of passivated III-V heterostructures

Structural and electronic properties of Al_0.3Ga_0.7As/GaAs heterojunction and GaAs pn junction systems are investigated by cross‐sectional scanning tunneling microscopy and spectroscopy (XSTM/S). The cross‐sectional samples were prepared by passivating ex situ with a sulfide [(NH₄)₂S] solution and were transferred into an ultra‐high vacuum system for STM/S studies. It is found that passivated samples are advantageous for the measurements of scanning tunneling spectroscopy. The STM/S results and the experimental details are reported.