Size dependence in hexagonal mesoporous germanium : pore wall thickness versus energy gap and photoluinescence.
A series of hexagonal mesoporous germanium semiconductors with tunable wall thickness is reported. These nanostructures possess uniform pores of 3.1-3.2 nm, wall thicknesses from 1.3 to 2.2 nm, and large internal BET surface area in the range of 404-451 m{sup 2}/g. The porous Ge framework of these materials is assembled from the templated oxidative self-polymerization of (Ge{sub 9}){sup 4-} Zintl clusters. Total X-ray scattering analysis supports a model of interconnected deltahedral (Ge{sub 9})-cluster forming the framework and X-ray photoelectron spectroscopy indicates nearly zero-valence Ge atoms. We show the controllable tuning of the pore wall thickness and its impact on the energy band gap which increases systematically with diminishing wall thickness. Furthermore, there is room temperature photoluminescence emission which shifts correspondingly from 672 to 640 nm. The emission signal can be quenched via energy transfer with organic molecules such as pyridine diffusing into the pores.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); National Science Foundation (NSF)
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 1000676
- Report Number(s):
- ANL/MSD/JA-68592; TRN: US201101%%458
- Journal Information:
- Nano Lett., Vol. 10, Issue Aug. 10, 2010
- Country of Publication:
- United States
- Language:
- ENGLISH
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