Abstract
We demonstrate Zn-diffusion InAs-based high-speed photodiodes (PDs) fabricated on semi-insulating (S.I.) GaAs substrates. The Zn-diffusion profile in our PDs is used to minimize the influence of the surface-state on the dark current, which is an issue for small (high-speed) InAs PDs with a large surface-to-volume ratio. Compared to control without Zn-diffusion, our device exhibits a much lower dark current. In addition, as compared to the performance reported for InAs PDs on conductive InAs substrates, our PDs on S.I. substrates demonstrate a lower parasitic capacitance and have a superior capability for being integrated with other microwave components. The measured optical-to-electrical (O-E) bandwidth of our device can be as wide as 20 GHz with a reasonable dark current density (∼50 A/cm2) at room temperature. Based on our modeling results, the measured bandwidths are limited by the internal electron drift/diffusion time due to the intervalley scattering effect under 1.55-μm wavelength excitation.
Original language | English |
---|---|
Article number | 5634077 |
Pages (from-to) | 100-102 |
Number of pages | 3 |
Journal | IEEE Photonics Technology Letters |
Volume | 23 |
Issue number | 2 |
DOIs | |
State | Published - 2011 |
Keywords
- InAs
- Zn-diffusion
- photodiodes