The Nd-nanocluster Si (nc-Si) coupling strength and its effect in excitation/de-excitation of Nd3+ luminescence in Nd-doped silicon-rich silicon oxide (SRSO) is investigated. Nd-doped SRSO thin films, which consist of nc-Si embedded inside a SiO2 matrix, were prepared by electron-cyclotron-resonance plasma-enhanced chemical vapor deposition of SiH4 and O-2 with cosputtering of Nd and subsequent anneal at 950 degreesC. Efficient Nd3+ luminescence with moderate temperature quenching is observed. Based on an analysis of the temperature dependence of Nd3+ luminescence lifetime, we find a coupling strength between nc-Si and Nd that is strong enough to result in efficient excitation of Nd3+ via quantum-confined excitons, while weak enough to result in a small back-transfer rate is identified as the key to Nd3+ luminescence. (C) 2003 American Institute of Physics.