Origin of electron accumulation at wurtzite InN surfaces

Ab‐initio theory of semiconductor band structures: New developments and progress

“…8, such a calculation yields a branch point energy B E that lies about 1 eV above the CBM in agreement with other estimates [85]. Measurements probing the conduction band electron plasma confirm the existence of electron accumulation at InN surfaces, with a surface Fermi level location near 1.58 ± 0.10 eV above the VBM [86].…”

Native point defects in CuIn1−xGaxSe2: hybrid density functional calculations predict the origin of p- and n-type conductivity

“…This means that there are donorlike surface states nearby the CBM, similar to e.g. in InN 27 . It provides a possible explanation for the experimentally observed n-type conductivity at the surface of CIGS with low x, resulting in a type-inversion of the surface compared with the usually p-type interior 28 .…”

Understanding the role of Si doping on surface charge and optical properties: Photoluminescence study of intrinsic and Si-doped InN nanowires

“…8,[19][20][21][22][23][24][25][26][27][28][29][30] For example, in general, the currently reported nominally undoped InN is n-type degenerate, with the residual electron densities in the range of ∼ 1 × 10 18 cm −3 , or higher. 8,11,25,[31][32][33][34] Moreover, it has been generally observed that there exists a very high electron concentration (∼ 1 × 10 13−14 cm −2 ) at both the polar and nonpolar grown surfaces of InN films, 19,35 and the Fermi-level (E F ) is pinned deep into the conduction band at the surfaces; 19,20,29,30 similar electron accumulation profile has also been measured at the lateral nonpolar grown surfaces of [0001]-oriented wurtzite InN nanowires. 8,11,21,22,25,36 In this regard, significant efforts have been devoted to understanding the fundamental surface charge properties of InN.…”

“…8,11,21,22,25,36 In this regard, significant efforts have been devoted to understanding the fundamental surface charge properties of InN. 20,23,27,29,30,[37][38][39] The electron accumulation at polar InN surface has been explained by the presence of large density of the occupied In-In bond states above the conduction band minimum (CBM), 23 as well as the unusual positioning of the branch point energy (E B ) well above the CBM at the Γ-point, which allows donor-type surface states to exist in the conduction band; 20 for polar InN surface, theoretical studies agree well with experiments. In terms of nonpolar InN surface, recent studies suggest that the surface electron accumulation may depend critically on the surface states, impurities, stoichiometry, and polarity; 27,37 and the absence of electron accumulation at nonpolar surface has been predicted.…”