High-Speed and High-Responsivity InP-Based Uni-Traveling-Carrier Photodiodes

Recent progress in InGaN-based photodetectors for visible light communication

“…In order to improve the light absorption of the In 0.53 Ga 0.47 As absorption layer and improve the responsivity of the device, a P-type electrode is used as the etching mask. 67 The results show that, for a 4 V reverse bias, the bandwidth is 103 GHz and the maximum responsivity is 0.6 A W À1 at a 100 mW optical input power. The introduction of dipoles promotes carrier migration and reduces carrier accumulation; this can effectively suppress the current blockage between the collection layer and the absorption layer, and reduce the carrier transit time.…”

“…Meng et al 67 proposed and prepared a dipole-doped UTCPD. They used molecular beam epitaxy (MBE) to grow an InGaAs/ InP dipole-doped structure and a retreat layer to lower the energy barrier.…”

Design guidelines for edge‐coupled waveguide unitravelling carrier photodiodes with improved bandwidth

“…8b shows the calculated impact of the absorber layer doping concentration on the bandwidth of the UTC PD. It has been proposed [19,20] that introducing step-like and gradient doping concentration profiles in the absorber layer lead to a speed up of electron diffusion towards the collector layer by forming a quasi-neutral electric field, which improves carrier transport [3]. Here we compare a constant doping concentration (1 × 10 19 cm −3 ) with graded doping concentrations in the absorber layer of the UTC PD.…”

“…Photodiodes (PDs) are used to convert optical signals into electric signals with several applications in optical communication and measurement systems [1], such as camera light meters. Large 3-dB bandwidth, high photocurrent and high responsivity are very important features of PDs for developing high capacity optical communication and fast measurement systems [2,3]. The unitravelling-carrier photodiode (UTC PD) is a relatively new type of PD whose main attraction is its capability for high bandwidth and high current operation [4].…”

Advances in High–Speed, High–Power Photodiodes: From Fundamentals to Applications

“…However, the introduction of quaternary system material (Figure 3b) might bring certain difficulties for epitaxial growth and the device fabrication process. Therefore, a dipole-doped regime, as shown in Figure 3b is incorporated to reduce the conduction band barrier, which uses a lower dipole-doping concentration (≤ 5 × 10 18 cm −3 to avoid out-diffusion) to fully suppress the conduction band offset only left with a spike-like barrier for electrons to tunnel through [50][51][52].…”