Photoelectric characteristics of CH3NH3PbI3/p-Si heteroj unction

Organic-inorganic hybrid perovskite CH3NH3PbI3 film is prepared on p-type silicon substrate using the one-step solution method to form a CHaNH3PbI3/p-Si heterojunction. The film morphology and structure are characterized by atomic force microscopy （AFM） and scanning electron microscopy （SEM）. The photoelectric properties of the CHaNHaPbIa/p-Si heterojunction are studied by testing the current-voltage （I-V） with and with- out illumination and capacitance-voltage （C-V） characteristics. It turns out from the I-V curve without illumina- tion that the CH3NH3PbI3/p-Si heterojunction has a rectifier feature with the rectification ratio over 70 at the bias of 4-5 V. Also, there appears a photoelectric conversion phenomenon on this heterojunction with a short circuit current （I sc） of 0.16 #A and an open circuit voltage （Voc） of about 10 mV. The high frequency C-V characteristic of the Ag/CH3NH3PbI3/p-Si heterojunction turns out to be similar to that of the metal-insulator-semiconductor （MIS） structure, and a parallel translation of the C-V curve along the forward voltage axis is found. This paral- lel translation means the existence of defects at the CH3NH3PbI3/p-Si interface and positive fixed charges in the CH3NH3PbI3 layer. The defects at the interface of the CH3NH3PbI3/p-Si heterojunction result in the dramatic decline of the Voc. Besides, the C-V test of CH3NH3Pbl3 film shows a non-linear dielectric property and the dielectric value is about 4.64 as calculated.