Comparison of InP Schottky diodes based on Au or Pd sensing electrodes for NO2 and O3 sensing

• Published in: Solid-state electronics 2012-06, Vol.72, p.29-37
• Main Authors: Varenne, C., Ndiaye, A., Brunet, J., Monier, G., Spinelle, L., Pauly, A., Bideux, L., Lauron, B., Robert-Goumet, C.
• Format: Article
• Language: English
• Subjects: Applied sciences; Contact; Detection; Diodes; Electronics; Engineering Sciences; Exact sciences and technology; Exposure; Gas sensor; General equipment and techniques; Gold; InP; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Interfaces; Materials; Micro and nanotechnologies; Microelectronics; Nitrogen dioxide; NO2; Palladium; Physics; Schottky diodes; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing; XPS
• ISSN: 0038-1101; 1879-2405
• DOI: 10.1016/j.sse.2012.02.003

► Simple and pseudo-Schottky diodes have been studied with two different metallic layers Au or Pd. ► Current–voltage analyzes was made to determine the barrier height and the ideality factor. ► The sensor was submitted from 20 to 100ppb of NO2 and O3 corresponding to the urban pollution. ► To understand the action of these gases on the sensitive layer XPS is performed. In previous reports, we have investigated on the influence of current transport mechanism on the sensitivity of InP Schottky and pseudo-Schottky diodes, for nitrogen dioxide detection. In this paper, the influence of the metal nature and the structure of the rectifying contact on the sensing layer are highlighted. More especially, we will focus on the behavior of these Schottky structures during and after their exposures to nitrogen dioxide (NO2) and ozone (O3). In this context, two types of structures have been studied: the simple Schottky diodes and the more elaborated structures called pseudo-Schottky. These diodes are realized with Au or Pd as metals. First, we will describe samples preparation and electrical characterization of the two types of structures. Then, we will compare sensor responses of these different structures under NO2 and O3. Finally, to better understand the action of these gases on the sensitive layer (the Schottky contact), X-rays photoelectron spectroscopy (XPS) is performed to follow the evolution of the metallic layer. The poisoning effect of active sites, which appears after NO2 and O3 expositions, is illustrated by comparative study of the active layer before and after exposure.