Extended Data Figure 2: Electron diffusion in an electrical injection device.

a, A device was fabricated to characterize charge diffusion in an electron-only electrically injected channel, with the structure shown here. Charges were injected into the C₆₀ channel by applying a 50 V pulse between the injecting contact and the silicon substrate for 5 s. b, The transient current collected at the buried contact. A steady-state current of 0.56 μA is observed approximately 3 s after the start of the pulse, with an exponential decay time of about 400 ms. A simulation of the turn-off transient using the same optically measured parameters for D and k in Table 1 for the DTDCPB-(10 nm C₆₀)-neat device is also shown in b (solid line). The small deviations of the fits to the electrical data are probably due to slow de-trapping of charges in the BPhen and SiO₂ that are injected during the 50 V pulse. Inset, photograph of the device with 1 cm scale bar.