ZnO optical microcavities have shown great promise as a potential core component material/structure for ultraviolet lasers, light-emitting diodes and photonic sensors because of their outstanding optoelectronic properties. Here, we report a novel ultra-thin-walled ZnO (UTW-ZnO) microtube cavity with a wall thickness of ~750 nm, supporting multiple types of optical modes, including in-tube Fabry–Perot modes, in-wall Fabry–Perot modes and wave-guided whispering gallery modes (WG-WGMs). The free-exciton recombination rate and exciton–exciton collisions are promoted in the cavity. The intensities of near-band edge (ultravoilet (UV) light) and X-band (blue light) emission are therefore increased at least one order of magnitude in the temperature range of 0–500 °C. Meanwhile, the temperature-sensitive multicolor luminescence of the UTW-ZnO microtubes in the visible band from near-white to bluish-violet is demonstrated for the first time. Low-threshold UV lasing is also achieved in the UTW-ZnO microtube by WG-WGMs, where the excitation threshold is down to 5.50 μW. Furthermore, light harvesting in the microtube cavity is beneficial to boosting the ZnO catalytic performance for photodegradation of organic dyes. The UTW-ZnO microtube exhibits compatibility to microfluidic channels for recyclable on-chip degradation. The present work provides new opportunities to design novel tubular wide-bandgap semiconductor devices for a variety of optoelectronic applications in micro/nanophotonics.

ZnO光学微腔具有出色的光电性能，因此有望作为紫外线激光器，发光二极管和光子传感器的潜在核心组件材料/结构。在这里，我们报道了一种新颖的超薄ZnO（UTW-ZnO）微管腔，其壁厚约为750 nm，支持多种类型的光学模式，包括管内Fabry–Perot模式，壁内Fabry–Perot模式和波音回音壁模式（WG-WGM）。腔内自由激子复合率和激子-激子碰撞得到促进。近频带边缘（紫外线（UV）光）和X的强度因此，在0-500°C的温度范围内，蓝带（蓝光）发射至少增加一个数量级。同时，首次展示了从近白色到蓝紫色的可见光波段中的UTW-ZnO微管的温度敏感多色发光。WG-WGM在UTW-ZnO微管中也实现了低阈值紫外线发射，其中激发阈值低至5.50μW。此外，在微管腔中收集光有利于提高用于有机染料光降解的ZnO催化性能。UTW-ZnO微管对微流体通道具有兼容性，可循环用于芯片上降解。本工作为设计用于微/纳米光子学中各种光电应用的新型管状宽带隙半导体器件提供了新的机会。