Pinnick Veronica, Rajagopalachary Sidhartharaja, Verkhoturov Stanislav V, Kaledin Leonid, Schweikert Emile A
Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255, USA.
Anal Chem. 2008 Dec 1;80(23):9052-7. doi: 10.1021/ac8014615.
We present secondary ion mass spectrometry (SIMS) data obtained from the bombardment of a novel nanomaterial with a suite of projectiles: Au1+, Au3+, Au9+, and Au400(4+). These are the first experiments where free-standing nano-objects were bombarded with kiloelectronvolt projectiles of atomic to nanoparticle size (Au400(4+)). The objects are aluminum monohydrate nanowhiskers, identified as crystalline boehmite (AlOOH) using X-ray diffraction. The nanoalumina is bonded to a microglass fiber that serves as a scaffold. The largest projectile, Au400(4+), has a diameter of approximately 2 nm, comparable to the nominal diameter of the nanowhiskers. There are notable differences in secondary ion (SI) response from sample volumes too small for full projectile energy deposition. The whisker spectra are dominated by small clusters--the most abundant species being AlO- and AlO2-. Bulk samples have larger yields for AlO2- than AlO-, whereas this trend is reversed in the whisker samples. Bulk samples give similar abundances of large SI cluster families [(Al2O3)(n)AlO2]- and [(Al2O3)(n)OH]-, whereas the whisker samples give an order of magnitude lower yield of these SIs. Given the nature of our experiments, i.e., the event-by-event bombardment/detection mode, we are uniquely able to obtain information from SIs emitted from single-projectile impacts. As such, effective yields were calculated in order to determine quantitative differences between the nano-objects and bulk samples.
Au1+、Au3+、Au9+和Au400(4+)轰击一种新型纳米材料而获得的二次离子质谱（SIMS）数据。这些是首次用原子到纳米颗粒尺寸（Au400(4+)）的千电子伏特射弹轰击独立纳米物体的实验。这些物体是一水合铝纳米晶须，通过X射线衍射鉴定为结晶勃姆石（AlOOH）。纳米氧化铝与用作支架的微玻璃纤维相连。最大的射弹Au400(4+)直径约为2 nm，与纳米晶须的标称直径相当。对于射弹能量无法完全沉积的过小样品体积，二次离子（SI）响应存在显著差异。晶须光谱以小簇为主——最丰富的物种是AlO-和AlO2-。块状样品中AlO2-的产率高于AlO-，而在晶须样品中这种趋势相反。块状样品中大型SI簇家族[(Al2O3)(n)AlO2]-和[(Al2O3)(n)OH]-的丰度相似，而晶须样品中这些SI的产率低一个数量级。鉴于我们实验的性质，即逐事件轰击/检测模式，我们能够独特地从单次射弹撞击发射的SI中获取信息。因此，计算了有效产率以确定纳米物体与块状样品之间的定量差异。
