Figure 1

Conduction band diagram of one period of an 8 μ m QCD showing the energy levels. Note that the ground state of the first QW belongs to the former period and is noted |down〉. The arrows illustrate the electronic path during a detection event. The layer sequence is as follows 67.8/56.5/19.8/39.6/22.6/31.1/28.3/31.1 /33.9/31.1/39.6/31.1/45.2/50.8 (the barriers are represented in bold types). The n-doping of the large QW is 5 × 10¹¹ cm^-2.