n -type β-FeSi2/intrinsic-Si/p-type Si heterojunction photodiodes for near-infrared light detection at room temperature

Abstract

n -Type β-FeSi2/intrinsic-Si/p-type Si heterojunctions, prepared by facing-targets direct-current sputtering, were evaluated as near-infrared photodetectors. The built-in potential was estimated to be approximately 1 V from capacitance-voltage characteristics. Diodes with a junction area of 0.03 mm2 exhibited a junction capacitance of 4.4 pF at zero bias. At room temperature, the devices exhibited responsivity of 140 mA/W and external quantum efficiency of 13% at a bias voltage of −5 V. The detectivity at zero bias was estimated to be 2.8×109 cm√Hz/W at the wavelength of 1.31 μm. These results indicate their high application potential as near-infrared photodiodes integrated with Si.

Epitaxial growth of n-type β-FeSi2thin films on p-type Si(111) substrates by radio-frequency magnetron sputtering and rectifying action of heterojunctions

“…β-FeSi2 has a large absorption coefficient, which is 200-fold larger than that of crystalline silicon at 1.5 eV, and possesses indirect and direct optical band gaps of 0.78 eV and 0.85 eV, respectively, which is relevant to an optical fiber for telecommunication wavelengths (1.3 and 1.5 μm) [3][4][5]. It is also compatible with silicon technology due to small lattice mismatches of 2 -5% [6,7].…”

n-Type β-FeSi2/p-type Si Near-infrared Photodiodes Prepared by Facing-targets Direct-current Sputtering

“…www.intechopen.com The photocurrent, resulted from the 1.31-m illumination, increased from 40 to 840 A with an increase in the reverse voltage from 0 to 5 V. The ratio of the photocurrent to the dark leakage current over the entire measured range of reverse voltages was approximately two orders of magnitude (Shaban et al, 2009b). The current responsivity increased from 6.6 to …”

“…Figure 10(a) shows the I-V characteristics of the n-type β-FeSi 2 /intrinsic-Si/p-type Si photodiodes, with an area of 3 mm 2 , measured in the dark and under the illumination of the 6-mW 1.31 m laser. The device exhibited good rectifying behavior with a rectifying ratio of greater than two orders of magnitude (Shaban et al, 2009b). The leakage current did not saturate and increased monotonously with the reverse voltage until the device experienced a thermal breakdown.…”

Minority-carrier diffusion length, minority-carrier lifetime, and photoresponsivity of β-FeSi2 layers grown by molecular-beam epitaxy

“…9,10 The photoresponsivity obtained for b-FeSi 2 thin films has been increasing each year. [11][12][13][14] However, the highest photoresponsivity obtained so far for b-FeSi 2 thin films (3.3 mA/W at 1.31 lm) 13 is still more than one order of magnitude smaller than that for n-type b-FeSi 2 single crystals. This difference is attributed to different minority-carrier diffusion lengths in b-FeSi 2 .…”