Recently, mixed-dimensional p-n heterojunctions have shown desirable optoelectronic functionalities. However, relatively little is known about the influence of interfacial traps on electron transport under external bias. Here, we explore the prominent dual optoelectronic characteristics of n-MoS2/p-GaN heterostructures, including photodetection and persistent photocurrent (PPC). The photoresponsivity was found to achieve as high as ∼105 A W−1 for 532 nm laser illumination under reverse bias. Additionally, the device exhibits the long-lasting PPC with a decay time constant (460 s) under forward bias. The results indicate that the hybrid heterojunctions not only function as high performance photodetectors under reverse bias but also have potential to use the unique property of PPC for other optoelectronic applications under forward bias alternatively.

No abstract

No abstract

The eye orbit has mechanical and acoustic characteristics that determine resonant frequencies and amplify acoustic signals in certain frequency ranges. These characteristics also interfere with the acoustic amplitudes and frequencies of eyeball when measured with an acoustic tonometer. A model in which a porcine eyeball was embedded in ultrasonic conductive gel in the orbit of a model skull was used to simulate an in vivo environment, and the acoustic responses of eyeballs were detected. The triggering source was a low-power acoustic speaker contacting the occipital bone, and the detector was a high-resolution microphone with a dish detecting the acoustic signals without contacting the cornea. Dozens of ex vivo porcine eyeballs were tested at various intraocular pressure levels to detect their resonant frequencies and acoustic amplitudes in their power spectra. We confirmed that the eyeballs’ resonant frequencies were proportional to intraocular pressure, but interference from orbit effects decreased the amplitudes in these resonant frequency ranges. However, we observed that the frequency amplitudes of eyeballs were correlated with intraocular pressure in other frequency ranges. We investigated eye orbit effects and demonstrated how they interfere with the eyeball’s resonant frequencies and frequency amplitudes. These results are useful for developing advanced acoustic tonometer.

No abstract