Sun X H, Wang S D, Wong N B, Ma D D D, Lee S T, Teo Boon K
Center of Super-Diamond & Advanced Film (COSDAF), Department of Biology and Chemistry, City University of Hong Kong, Hong Kong SAR, China.
Inorg Chem. 2003 Apr 7;42(7):2398-404. doi: 10.1021/ic020723e.
Attenuated total reflection Fourier transform infrared (FTIR) spectroscopy was used to characterize the surface species on oxide-free silicon nanowires (SiNWs) after etching with aqueous HF solution. The HF-etched SiNW surfaces were found to be hydrogen-terminated; in particular, three types of silicon hydride species, the monohydride (SiH), the dihydride (SiH(2)), and the trihydride (SiH(3)), had been observed. The thermal stability of the hydrogen-passivated surfaces of SiNWs was investigated by measuring the FTIR spectra after annealing at different elevated temperatures. It was found that hydrogen desorption of the trihydrides occurred at approximately 550 K, and that of the dihydrides occurred at approximately 650 K. At or above 750 K, all silicon hydride species began to desorb from the surfaces of the SiNWs. At around 850 K, the SiNW surfaces were free of silicon hydride species. The stabilities and reactivities of HF-etched SiNWs in air and water were also studied. The hydrogen-passivated surfaces of SiNWs showed good stability in air (under ambient conditions) but relatively poor stability in water. The stabilities and reactivities of the SiNWs are also compared with those of silicon wafers.
采用衰减全反射傅里叶变换红外（FTIR）光谱对无氧化物硅纳米线（SiNWs）在氢氟酸水溶液蚀刻后的表面物种进行表征。发现经氢氟酸蚀刻的SiNW表面以氢原子终止；特别地，观察到了三种硅氢化物物种，即单氢化物（SiH）、二氢化物（SiH₂）和三氢化物（SiH₃）。通过测量在不同升高温度下退火后的FTIR光谱，研究了SiNWs氢钝化表面的热稳定性。发现三氢化物的氢脱附发生在约550 K，二氢化物的氢脱附发生在约650 K。在750 K及以上，所有硅氢化物物种开始从SiNWs表面脱附。在约850 K时，SiNW表面没有硅氢化物物种。还研究了经氢氟酸蚀刻的SiNWs在空气和水中的稳定性和反应性。SiNWs的氢钝化表面在空气中（在环境条件下）表现出良好的稳定性，但在水中的稳定性相对较差。还将SiNWs的稳定性和反应性与硅片的稳定性和反应性进行了比较。
