Defect Reconstruction Triggered Full-Color Photodetection in Single Nanowire Phototransistor

Abstract

The coherent developments of high performance broadband photodetection and a discrimination technique are highly essential for multiscene imaging and optical communication applications. The integration of traditional bandpass filters or stacking other spectral absorber in photodetectors often complicates the device design and leads to asymmetric photogain for each waveband. Herein, we report on ultraviolet–visible (UV-vis) multispectral photodetection based on a single ZnO nanowire (NW) phototransistor, where defect reconstructions can be reliably induced by a two-step annealing that leads to the observed broadband photodetection. Electron paramagnetic resonance and photoluminescence spectra reveal the reconstructions of zinc-atom-related defects (i.e., zinc interstitials and vacancies). Combined microdifferential reflectance and multimode scanning probe microscope (SPM) technique confirm the presence of a unique visible-sensitive Zn-rich ZnO shell layer and a trap-free UV-sensitive ZnO core. We achieve not only an ultrahigh carrier mobility (212.4 cm2 V–1 s–1), but also a concurrent improvement for UV-vis photodetection with superior responsivities and detectivities on the orders of 105 AW–1 and 1015 Jones at 100 mV, respectively, and response speeds less than one second. Moreover, photocurrents under blue, green, and red stimuli can be selectively switched on/off by tuning the gate stress. These high performances in all figures of merit have opened new routes to tailor intrinsic properties of a single NW for optoelectronic applications.

Layer‐Dependent Optoelectronic Properties of 2D van der Waals SnS Grown by Pulsed Laser Deposition

“…The optimal D * is as large as 9.78 × 10 10 cm Hz 1/2 W −1 owing to the very small I d . The SnS photodetectors with large D * are suitable for detection within a broad wavelength range and for very weak optical signals 67…”

In Situ Formed Gradient Bandgap‐Tunable Perovskite for Ultrahigh‐Speed Color/Spectrum‐Sensitive Photodetectors via Electron‐Donor Control

“…All photodetectors exhibit a fast response toward all light with visible wavelengths. A response time down to 71 ns is obtained, several orders of magnitude lower when compared with that of other filterless color/spectrum‐sensitive photodetectors,5,9–14,16,19,45–47 (Table S5, Supporting Information), which can be further accelerated by reducing the device area. It should also notice that our device which works at the self‐powered mode shows higher responsivity than other color detectors based on perovskite, even all of them required additional voltage bias.…”

2D Allotrope of Carbon for Self‐Powered, Flexible, and Transparent Optoelectronics

“…The well‐defined heterointerface is subjected to the type II band alignment, as shown by the band diagram in Figure a. This alignment is deduced from two facts: i) ZnO and conventional α‐C(:H) are naturally n‐type and p‐type, respectively; [ 19,34,35 ] ii) the type I (straddling gap) and type III (broken gap) alignments are precluded in our devices, as discussed in Figure S6 (Supporting Information). The interface staggering gap formed by the type II band alignment gives rise to a build‐in potential, efficiently separating and migrating the photogenerated carriers even under the sub‐band optical exposure.…”