Strak Pawel, Miller Wolfram, Krukowski Stanislaw
Institute of High Pressure Physics, Polish Academy of Sciences, Sokolowska 29/37, 01-142 Warsaw, Poland.
Leibniz Institute for Crystal Growth (IKZ), Max-Born-Str. 2, D-12489 Berlin, Germany.
Materials (Basel). 2024 May 29;17(11):2614. doi: 10.3390/ma17112614.
It was demonstrated by ab initio calculations that energy optimization in the reconstruction of semiconductor surfaces is controlled by the global charge balance. The charge control was discovered during simulations of the influence of heavy doping in the GaN bulk, which changes to ratio in the reconstruction of stoichiometric GaN(0001), i.e., a Ga-polar surface. Thus, the reconstruction is not limited to the charge in the surface only; it can be affected by the charge in the bulk. The discovered new reconstruction of the GaN(0001) surface is (4 × 4), which is different from the previously reported (2 × 1) pattern. The undoped GaN reconstruction is surface charge controlled; accordingly, (3/8) top-layer Ga atoms remain in a standard position with hybridized bonding, while the remaining (5/8) top-layer Ga atoms are shifted into the plane of N atoms with hybridized bonding. The change in the charge balance caused by doping in the bulk leads to a change or disappearance of the reconstruction pattern.
从头算计算表明，半导体表面重构中的能量优化受整体电荷平衡控制。在对GaN体相中重掺杂影响的模拟过程中发现了电荷控制，重掺杂改变了化学计量比的GaN(0001)（即Ga极性表面）重构中的比例。因此，重构不仅限于表面电荷；它会受到体相电荷的影响。发现的GaN(0001)表面的新重构为(4×4)，这与先前报道的(2×1)图案不同。未掺杂的GaN重构受表面电荷控制；相应地，(3/8)的顶层Ga原子保持在具有杂化键的标准位置，而其余(5/8)的顶层Ga原子则以杂化键转移到N原子平面中。体相中掺杂引起的电荷平衡变化导致重构图案的改变或消失。
