Electrical Properties of Sulfonated Polyaniline Thin Film Grown on Different GaAs Substrates

Abstract

The paper describes the impact of the crystallographic orientation of an n-type GaAs substrate on the electrical properties of a sulfonated polyaniline (SPAN) thin film with a thickness of 120 nm grown on different n-type GaAs substrates orientation, which are (100), (311)A, and (311)B GaAs planes. Electrical characterization was performed by using current density-voltage (J−V) at room temperature and different temperatures (60−360 K). An ideality factor (n), a Schottky barrier height (Φb), and an activation energy (E a) were extracted from forward J−V characteristics. From the J−V results, it was obtained that the rectification value at 0.5 V for the SPAN/(311)B GaAs hybrid device is higher than those for SPAN grown on the (100) and (311)A GaAs planes. Furthermore, as the temperature of the three heterojunction devices rises, the value of Φ b increases, n drops, and E a rises. The E a measurements revealed that E a for the SPAN/(311)B n-type GaAs heterostructure is lower than those for SPAN samples grown on the (100) and (311)A n-type GaAs planes. This could be related to the low number of defects in SPAN/(311)B than the other two samples. These results make SPAN with a thickness of 120 nm grown on the high index GaAs planes an interesting hybrid device for future devices applications.

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“…120 nm grown on n-GaAs substrates with different orientations ((100), (311) A, and (311) B were studied by Jaqsi et al [112] They observed that the SPAN/(311) B n-GaAs device has better electrical performances than the SPAN/(100) and SPAN/(311) A n-GaAs devices. However, defects caused by the presence of an oxygen layer on GaAs substrates are the major factors limiting the performance of these devices.…”

“…However, if the highest occupied molecular orbital (HOMO) level of the HTL polymer is lower than the VBM of GaAs, the higher valence band maximum (VBM) of (111) B than that of (100) may lead to increased complexation due to blocked hole transport, as the band structure alignment shown in Figure 3g. More recently, the electrical characteristics of sulfonated polyaniline (SPAN) with a thickness of 120 nm grown on n‐GaAs substrates with different orientations ((100), (311) A, and (311) B were studied by Jaqsi et al [ 112 ] They observed that the SPAN/(311) B n‐GaAs device has better electrical performances than the SPAN/(100) and SPAN/(311) A n‐GaAs devices. However, defects caused by the presence of an oxygen layer on GaAs substrates are the major factors limiting the performance of these devices.…”