Anomalous temperature dependence of electron tunneling between a two-dimensional electron gas and Si dots

We present our observation of an anomalous temperature and optical excitation intensity dependence of the electron tunneling between a two-dimensional electron gas (2DEG) and Si dots in the direct tunneling mode. We find that the gate voltages required for the electron injection from the 2DEG to Si-dots become smaller with increase in the temperature or in the optical excitation intensity. The experimental results are discussed in terms of the geometrical matching of the wave functions of a 2DEG and an electron in a Si-dot.