The unusually high lattice thermal conductivity of semiconducting cubic boron arsenide (BAs) has motivated studies of the bulk electronic band structure of BAs for its potential use as an active layer material in electronic devices. However, the surface electronic structure of BAs remains to be investigated. Scanning tunneling spectroscopy (STS) is employed here to probe the electronic structure of as-grown and in situ cleaved surfaces of BAs single crystals. The bandgap measured at several interior locations of the cleaved surface is about 2.1 eV, close to our calculated bulk bandgap value of 2.05 eV. In comparison, the measured bandgap within several micrometers from the two edges of the cleaved surface decreases to about 1.9 eV. This decrease is attributed to tunneling from an increased concentration of shallow acceptors. Several of the tunneling peaks observed by STS within the bandgap are close to the calculated energy levels for bulk lattice defects and substitutional impurities. In contrast to some other III–V compound semiconductors where surface relaxation prevents intrinsic surface states from appearing in the bulk bandgap, some measured tunneling peaks in the BAs bulk bandgap can contain contributions from intrinsic surface states calculated for boron dangling bonds.

半导体立方砷化硼 (BAs) 异常高的晶格热导率激发了对 BAs 体电子能带结构的研究，因为它有可能用作电子器件中的活性层材料。然而，BAs的表面电子结构仍有待研究。这里采用扫描隧道光谱 (STS) 来探测生长和原位的电子结构BAs 单晶的切割面。在解理表面的几个内部位置测量的带隙约为 2.1 eV，接近我们计算的 2.05 eV 的体带隙值。相比之下，离解理表面两个边缘几微米内的测量带隙减小到约 1.9 eV。这种减少归因于浅受体浓度增加的隧道效应。STS 在带隙内观察到的几个隧道峰接近计算的体晶格缺陷和置换杂质的能级。与其他一些 III-V 族化合物半导体相比，表面弛豫会阻止本征表面态出现在体带隙中，