Electronic properties of c-BN/diamond heterostructures for high-frequency high-power applications

TL;DR

This study uses first principles calculations to analyze diamond/c-BN heterostructures, revealing their potential for high-frequency, high-power electronic devices due to favorable band alignments and interface charge polarization.

Contribution

It provides a detailed theoretical investigation of band offsets and interface polarization in diamond/c-BN heterostructures, highlighting their suitability for advanced electronic applications.

Findings

(111) and (100) structures exhibit type-I band alignment

Non-polar (110) structure may form type-II alignment

Heterostructures show charge polarization and potential for 2D conductive channels

Abstract

Using first principles calculations, this work investigates the suitability of diamond/c-BN heterojunctions for high frequency, high power device applications. The key quantities of band offsets and interface charge polarization are examined for different crystallographic orientations [(110), (111), or (100)], bond terminations (C-B or C-N), and substrates (diamond or c-BN). The results indicate that both the (111) and (100) structures with polar interfaces are likely to be a type-I alignment with the diamond conduction and valence band extrema nested within the c-BN bandgap, whereas the non-polar (110) counterpart may form type II as the valence band of c-BN is shifted down substantially lower. The (111) and (100) structures also show net charge polarization in a narrow region at the interface. The electron-deficient and electron-rich nature of the C-B and C-N bonding are found to induce charge redistribution leading to an essentially 2D sheet of negative and positive polarization. With the predicted band alignments suitable for carrier confinement as well as the possibility of the modulation and polarization doping, the diamond/c-BN heterostructures are a promising candidate for high-performance electronic devices with a highly conductive 2D channel. Both p-type and n-type devices appear possible with a judicious choice of the heterojunction configuration.