Electrical Properties Of Amorphous Selenium (aSe)/p-Type Silicon (pSi) Heterojunction Devices

Abstract

Herterojunction devices are fabricated by vacuum deposition of selenium films (aSe) on four chemically etched p-type silicon crystals (pSi) each of 5Ω-cm resistivity and carrier concentration of 2.8x10¹⁵cm^-3. Two of the pSi crystals have surface orientation of (111) while the other two crystals have (100) surface orientation. Two of the devices are annealed in a vacuum of about 10^-4 torr at a temperature of 423k (150^oC) for 30 minutes. Current-voltage measurements of both annealed and unannealed junction devices are performed at room temperature, 298k (25^oC).

The junction devices exhibit rectification property. The electrical conductivity in annealed junction is lower than in its unannealed counterpart for devices fabricated on pSi crystals having the same surface orientation. Barrier heights obtained in junctions fabricated on pSi (100) crystals are larger than barrier heights on pSi (111) crystals.

KEY WORDS: Heterojunction , device, amorphous, annealing

Global Journal of Pure and Applied Sciences Vol.11(2) 2005: 297-300