Analysis of Schottky barrier height in Al/p-SiNWs/Al and Al/n-SiNWs/Al heterojunction diodes and its influence on charge transport characteristics

This study investigates two types of silicon nanowires (SiNWs)-based Metal-Semiconductor-Metal (MSM) devices are synthesized: Al/p-SiNWs/Al and Al/n-SiNWs/Al in an effort to compare the electrical behavior of p-type and n-type SiNWs. The nanowires are prepared via metal-catalized chemical etching (MCCE), an inexpensive and scalable method for forming uniform, large-area SiNWs. The electrical properties of Al/p-SiNWs/Al and Al/n-SiNWs/Al Schottky barrier diodes (SBDs) are mainly controlled by the Schottky barrier height (SBH), carrier mobility, and interface effects. These electrical characteristics explore that Al/p-SiNWs/Al diode has a relatively higher SBH of 0.13 eV and provides a forward current of 2.11 × 10⁻ 5 A at + 10 V, while the Al/n-SiNWs/Al structure, with a reduced SBH of 0.11 eV, provides a higher forward current of 3.03 × 10⁻⁴ A at + 10 V, because of the high electronic conductivity and favorable band bending with the metal contact. Moreover, Al/p-SiNWs/Al device shows relatively higher ideality factor (6.82) than the Al/n-SiNWs/Al (5.66), because of the lower slop in the I-V characteristics which may be due to the enhanced recombination rate and barrier inhomogeneity at the Al/p-SiNWs contact. Additionally, analyses of photosensitivity, photoresponsivity and detectivity have been carried out to confirm the optical-to-electrical conversion efficiency of the p and n-SiNWs based MSM devices for high-sensitivity and low-light photodetection applications.