Magnesium-Silicide (Mg2Si)/Silicon (Si) Heterojunction Based TFET for Optical Detection at 1550 nm

In this work, a novel proposal of Magnesium-Silicide (Mg2Si)/Silicon (Si) Heterojunction based GeTFET for optical detection at 1550 nm has been offered where the merits of Mg
2
Si as source material and its performance both under dark and illumination has been discussed. Additionally, the source material engineering over GeTFET has been done with other low band gap materials such as Ge and SiGe and their performance has been compared with devices having Mg
2
Si and Si as source materials. The results reveal that in dark condition the proposed device i.e. Mg
2
Si based GeTFET outperforms other device designs i.e. with Si, Ge and SiGe in terms of high Ion (2.56×10
^-4
A/µm), high I
on
-to-I
off
ratio (3.43×10
¹¹
) at gate voltage of 1.0V and low threshold voltage (0.43V) at drain bias of 0.5V. As far as the optical performance is concerned, the proposed device with Mg2Si source material offers significantly higher sensitivity of 9.38×10
⁷
at such a low power of 10
^-4
µW/µm
²
which is approximately 3 orders higher than other aforementioned materials. Moreover, the proposed architecture offers much better response and detection capability having responsivity of 8.8×10
³
A/W and detectivity 1.75×10
¹⁶
Jones at comparable low optical power density of 7×10
^-4
µW/µm
²
.