Tóm tắt

The n-TiO2/polyphenylene (PPh)/p-Si heterojunction devices were fabricated in which PPh film and TiO2 toprnlayer were grown on p-Si substrates by diazonium modification method and cathodic electrodeposition,rnrespectively. The XPS, UV–vis diffuse reflectance and STM analyses of the films were performed. After therncharacterization of deposited films and the fabrications of n-TiO2/PPh/p-Si sandwich devices, the electricalrnmeasurements of nine devices were carried out from the current–voltage (I–V) characteristics, at room temrnperature. The I–V characteristics of n-TiO2/PPh/p-Si heterojunctions were compared with TiO2/p-Si heterornjunctions, one of them was analysed in more detailed and it was observed that the n-TiO2/PPh/p-Si gave betterrnperformance than TiO2/p-Si heterojunctions such that lower ideality factor, higher rectification ratio and morernstable reverse current characteristics. Then, the main device parameters of n-TiO2/PPh/p-Si were compared withrnmany devices reported in literature based on TiO2/p-Si device and TiO2 preparation techniques. Furthermore, thernrectification ratio of n-TiO2/PPh/p-Si heterojunction was 9.42 × 105, while it was 5.80 × 102 for TiO2/p-Sirnheterojunction. Later, the capacitance-voltage (C–V) and conductance-voltage (G-V) measurements of the nrnTiO2/PPh/p-Si heterojunction was performed depending on applied frequency and bias and it was observed thatrnthe values of capacitance and conductance were found a strongly function of bias voltage.