Ultrawide bandgap (UWBG) semiconductors inherently exhibit very high electrical resistivities. This property presents not only challenges in probing their electrical transport properties but also difficulties to fabricate, understand, and characterize the electrical properties of metal contacts on these materials. Here, we report the measurements and analysis of the applied electric field dependence of photocurrent to reveal the effect of metal contacts on the transport properties of highly resistive h-BN. Our results indicate that even for h-BN with a room temperature resistivity as high as 1014 Ω cm, the as-deposited metal contact is not a completely blocking type as commonly assumed in previous analyses for other large bandgap insulating materials. By modifying the boundary condition between the metal/semiconductor interface, a quantitative description has been obtained, which can be used to determine if the metal contact is Ohmic or blocking type. This quantitative description should be applicable to all UWBG semiconductors with extremely high electrical resistivities. The work also provides a better understanding of how the metal contact type affects the transport properties of UWBG semiconductors in general.

中文翻译：

---

高阻超宽带隙半导体的光电流和金属接触特性

超宽带隙 (UWBG) 半导体本质上表现出非常高的电阻率。这种特性不仅给探测其电传输特性带来了挑战，而且还给制造、理解和表征这些材料上金属触点的电特性带来了困难。在这里，我们报告了光电流的外加电场依赖性的测量和分析，以揭示金属接触对高阻 h-BN 输运特性的影响。我们的结果表明，即使对于室温电阻率高达 1014 Ω cm 的 h-BN，沉积态金属接触也不是像之前对其他大带隙绝缘材料的分析中通常假设的完全阻挡类型。通过修改金属/半导体界面之间的边界条件，获得了定量描述，可以用来确定金属接触是欧姆接触还是阻挡型接触。这种定量描述应该适用于所有具有极高电阻率的 UWBG 半导体。这项工作还让我们更好地了解金属接触类型如何影响 UWBG 半导体的传输特性。