Properties of hydrogen molecules in semi-conductors

氢现在被认为是半导体中最重要和最容易理解的杂质之一，尽管“最简单”的氢相关缺陷- H2 -仅在Si和GaAs中被检测到，并且仍然是研究较少的缺陷之一。H2最不寻常的是Si中间隙H2的（I = O）段核自旋态在室温退火和坏间隙光照射下不稳定。这一最近发现的现象可以用H2在不同核自旋状态下的不同扩散速率来初步解释。因此，对氢气扩散的详细研究是本项目的首要任务。在Si， Ge和GaAs中，高浓度的氢会产生扩展的平面缺陷，称为血小板。在一定条件下，这些小行星可以在高压下保存H2气体。如果这个新的二维玻色系统被冷却到合适的温度，存在两种可能性。根据分子和宿主之间的相互作用势，H2气体要么形成二维晶体结构，要么经历玻色-爱因斯坦凝聚。从科学的角度来看，这两种可能性都非常有吸引力，使二维H2气体的研究成为该项目的主要任务。拉曼散射和傅里叶变换红外光谱技术将被用来实现上述目标。

Hydrogen is now considered as one of the most important and well-understood impuirties in semiconductors though the 'simplest' possible H-related defect - H2 - was detected only in Si and GaAs and remains one of the less studied ones. The most unusual thing about H2 is that para (I = O) nuclear spin state of interstitial H2 in Si is not stable with respect to room temperature annealing and illimination with the bad gap light. This recently found phenomenon was tentatively explained by different diffusion rates of H2 in different nuclear spin states. Thus, detailed investigation of the H2 diffusion is the first task of the proposed project. In Si, Ge and GaAs high concentrations of hydrogen create extended planar defects called platelets. Under certain conditions these plavelets may hold H2 gas under high pressure. Two possibilities exist if this novel two-dimensional Bose system is cooled down to appropriate temperatures. Depending on the interacting potential between the molecules and the host, the H2 gas either forms a 2D crystalline structure or experiences Bose-Einstein condensation. Both possibilities are very attractive from a scientific point of view, making the study of 2D H2 gas a major task of the project. Raman scattering and Fourier tansform infrared spectroscopy are techniques to be employed to fulfill the goals outlined above.