Increase in the conductivity and work function of pyrosol indium tin oxide by infrared irradiation

Abstract

The effect of infrared (IR) radiation on an indium tin oxide (ITO) transparent conductor, prepared by a pyrosol method, was investigated. As-deposited ITO was irradiated with IR in nitrogen gas at atmospheric pressure and temperatures ranging from 50 to 430 °C.Typically, IR irradiation of the as-deposited ITO at 400 °C for 60 minutes reduced the electrical resistance by 60%, raised the work function by 0.5 eV, and enlarged the optical energy band gap by 0.05 V. The resistance was mainly decreased during the initial 10 minutes of irradiation. The results of field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) analysis showed that the IR irradiation enhanced the crystallinity of the ITO. These results, derived from treatment at atmospheric pressure and using inexpensive equipment, suggest that IR irradiation should be an inexpensive method to reduce the resistance and raise the work function of as-deposited pyrosol ITO.

Study on the ITO work function and hole injection barrier at the interface of ITO/a-Si:H(p) in amorphous/crystalline silicon heterojunction solar cells

“…The improvement in the F ITO was supposed to be due to crystallinity of ITO films as less stable bonding are converted to more stable bonding of crystal by increasing T s , thereby increasing the work function of ITO films. The augmentation of crystallinity in ITO films was indicated by XRD images [17,18] as shown in Fig. 2. The reduction in the level of hole injection barrier (F HB ) can form ohmic contacts.…”

Physical and Technological Aspects of Solar Cells Based on Metal Oxide-Silicon Contacts with Induced Surface Inversion Layer

“…The work function of the ITO films fabricated by pyrosol technique was reported around 4.8 eV, without an additional thermal treatment, whereas it was around 5.2 eV after a thermal treatment [13].…”

Efficient Silicon Solar Cells Fabricated with a Low Cost Spray Technique

“…Furthermore, the thermal grown intermediate SiO x layer always presents a positive fixed charge located at the SiO x /Si interface, which decreases the barrier height in the case of n-type silicon. Using known data for the work function of ITO films deposited by spray pyrolysis, whose average value is reported as 5.0 eV (Nakasa et al, 2005, Fukano, 2005, and the electron affinity of silicon as 4.05 eV, the ideal barrier height between ITO and n-type silicon is 0.95 eV according to the Mott-Schottky theory. After a treatment of the n-type silicon surface in the hydrogen-peroxide (H 2 O 2 ) solution with a controlled temperature (60 0 C) during 10 minutes, a barrier height of 0.9 eV was obtained with capacitance-voltage measurements.…”