WORK FUNCTION AND AFFINITY CHANGES ASSOCIATED WITH THE STRUCTURE OF HYDROGEN-TERMINATED DIAMOND (100) SURFACES
WORK FUNCTION AND AFFINITY CHANGES ASSOCIATED WITH THE STRUCTURE OF HYDROGEN-TERMINATED DIAMOND (100) SURFACES
复制标题
与氢封端金刚石 (100) 表面结构相关的功函数和亲和力变化
DOI：
--
复制
发表时间：
1998
期刊：
影响因子：
--
通讯作者：
A. Mills
中科院分区：
文献类型：
--
作者：
G. Brandes;A. Mills
金刚石~100！使用正电子再发射和开尔文探针技术测量表面，以揭示化学势、表面偶极子和能带弯曲的变化。正电子亲和力x1是负的;在20 ° C和100 °C之间的温度下，我们发现x1 524.2060.04 eV的（231）重建，无氢表面，23.7660.04 eV的单氢化物表面，和23.0360.04 eV的完全氢化表面。对于电子功函数w2观察到类似的幅度，但相反的符号变化。随着氢的加入，x1的室温值增加，而w2的室温值减小，这与理论结果一致。（231）表面的正电子亲和力几乎与温度无关，表明表面几乎不含氢，由p-键合的二聚体组成。随着温度的升高，单氢化物表面的正电子亲和力在（575650）°C时降低到最小值24.08 eV，并在800 °C时恢复到室温值。我们推测复杂的温度依赖性是由氢原子的二维阵列的波动或相变引起的。相反的假设，带弯曲的主要贡献的金刚石接触电位的变化，小带弯曲是显而易见的，在室温下的各种制备的未掺杂的金刚石表面。然而，在升高的温度下的正电子产率的实质性变化是一致的形成一个正电场，由于3 310厘米的表面电子占据状态与吸收的氧或结构缺陷。@S0163-1829 ~98！02832-X编号
The positron and electron work functions and affinities of diamond ~100! surfaces were measured using positron reemission and Kelvin probe techniques to reveal changes in the chemical potential, surface dipole, and band bending. The positron affinity x1 is negative; at temperatures between 20 and 100 °C we find x1 524.2060.04 eV for the (231) reconstructed, hydrogen-free surface, 23.7660.04 eV for the monohydride surface, and23.0360.04 eV for a fully hydrogenated surface. Similar magnitude, but opposite sign changes are observed for the electron work function w2 . The increases in the room-temperature values of x1 and the decreases inw2 as hydrogen is added are in agreement with theoretical results. The positron affinity of the (231) surface is nearly temperature independent, indicative of a surface that is nearly hydrogen-free and consisting ofp-bonded dimers. As the temperature is raised, the positron affinity of the monohydride surface decreases to a minimum of 24.08 eV at (575650) °C and returns to the room-temperature value by 800 °C. We speculate that the complex temperature dependence is caused by fluctuations or phase transitions of the two-dimensional array of hydrogen atoms. Contrary to assumptions that band bending is the major contribution to changes in the contact potential of diamond, little band bending is evident at room temperature for variously prepared undoped diamond surfaces. Nevertheless, substantial changes in the positron yield at elevated temperatures are consistent with the formation of a positive electric field due to 3 310 cm surface electrons occupying states associated with absorbed oxygen or structural defects. @S0163-1829 ~98!02832-X#