Infrared transient absorption and excited-states of excitons and biexcitons confined in CuCl quantum dots

Mid-infrared picosecond transient absorption has revealed a new aspect of the excited states of confined biexcitons in CuCl quantum dots embedded in a NaCl matrix. The transient absorption exhibits two-decay components that originate from confined excitons and biexcitons. The attribution of the fast-decay component to the confined biexcitons has been confirmed by measurement by a two-photon resonant excitation process. The transient-absorption spectrum of biexcitons indicates the existence of a stable biexciton excited state in the quantum dots, in contrast to the unstable excited state in the bulk crystal. (C) 2004 Elsevier B.V. All rights reserved.

中红外皮秒瞬态吸收揭示了嵌入氯化钠基质中的氯化铜量子点中受限双激子激发态的一个新方面。瞬态吸收呈现出两个衰减分量，它们源自受限激子和双激子。通过双光子共振激发过程的测量，已证实快速衰减分量归因于受限双激子。双激子的瞬态吸收光谱表明量子点中存在稳定的双激子激发态，这与块状晶体中的不稳定激发态形成对比。（C）2004爱思唯尔公司。版权所有。