Strain effects on electronic properties of diamond surfaces

Diamond is a wide-bandgap semiconductor with tremendous potential as an electronic device material for power RF applications. In spite of theoretically predicted superior device performance, the high-frequency operation of p-type diamond field-effect transistors (SDFETs) are limited by lower carrier mobilities and charge densities at the surface [2]. These drawbacks are in part due to inter-band scattering of hybridized, degenerate heavy-hole (HH) and light-hole (LH) states near the valance band (VB) edge [3]. Motivated by this, we investigated the effect of biaxial in-plane strain on the electronic properties and carrier dynamics of hydrogenated diamond surfaces (100 and 110) using first principle method. For both the surfaces, a small amount of biaxial tensile strain (< 1%) breaks the degeneracy and lifts the LH band above the HH state and results in the VB band warping. These strain-induced collective phenomena modify VB characteristics and contribute to a reduction in the charge carrier (hole) effective mass leading to an increment in the hole mobility and densities at the surface. 1. Chris J. H. Wort and et al., Materials Today, Vol 11, No. 1-2, 2008. 2. P.B. Shah and et al., MRS Advances, Vol 2, No. 41, 2017. 3. D. Zhang and et al., In. Symp. VLSI Tech. Dig., P 26-27, 2005