AB-INITIO CALCULATION OF ELECTRON-AFFINITIES OF DIAMOND SURFACES

The electron affinity (EA) of various terminations of diamond surfaces has been calculated by the ab initio pseudopotential method. The bare , reconstructed (100) and (111) surfaces are found to have positive EA 's of 0.5 and 0.35 eV, respectively. The hydrogen-terminated surfaces 1x1(100):2H, 2x1(100):H, and (Ill):H have sizable negative EA's of ord er -2.4, -2.0, and -2.0 eV, respectively. A symmetrical canting was fo und to be the most stable geometry for the 1x1(100):2H surface. The ox ygen-terminated surfaces have positive affinities of +2.6 eV for the m ore stable ether configuration, while the OH termination has a negativ e EA. The various values can be understood in terms of the surface dip ole of the terminating bond. [S0163-1829(98)04412-9].