We prepared ZnO nanostructures on three different substrates such as quartz, sapphire (Al₂O₃) (001) and MgO (100) by glancing angle deposition (GLAD) technique using KrF excimer pulsed laser and investigated the effects of various substrates on the growth and optical properties. The GLAD technique promotes a vertical growth of the nanostructures and hence creates necessary porosity for penetration of light through the top of the surface. Although these nanostructures are porous, they are highly crystalline and oriented along c-axis of the wurtzite structure. Notably, despite the amorphous nature of the quartz substrate, nanostructures on quartz are preferentially oriented towards the c-axis. All three samples show intense ultraviolet (UV) emission with a highly suppressed visible emission, where the suppression depends on the growth and porous morphology of nanostructures. The variation in morphology and the porosity strongly influenced the electrical properties and UV photo-detection of these nanostructures when exposed under UV (254 nm) light. Although we used the same technique of the growth, the lowest dark current (0.14 nA) with the highest UV photosensitivity (182 %) is achieved for the highly porous and yet crystalline nanostructures grown on the sapphire substrate. Generally, it is extremely difficult to maintain crystalline structure with porosity; however, here we demonstrate a promising approach in designing visible-blind photodetectors by combining these two opposites, porosity and crystallinity, in ZnO nanostructures using the GLAD-assisted pulsed laser deposition method.

我们使用KrF准分子脉冲激光通过掠角沉积（GLAD）技术在石英，蓝宝石（Al ₂ O ₃）（001）和MgO（100）等三种不同的基底上制备了ZnO纳米结构，并研究了各种基底对生长的影响和光学特性。GLAD技术可促进纳米结构的垂直生长，因此可产生必要的孔隙率，以使光穿透表面顶部。尽管这些纳米结构是多孔的，但是它们是高度结晶的并且沿着纤锌矿结构的c轴取向。值得注意的是，尽管石英基板具有非晶性质，但石英上的纳米结构优先朝向c-轴。这三个样品均显示出强烈的紫外线（UV）发射，并具有高度抑制的可见光发射，其中抑制取决于纳米结构的生长和多孔形态。当暴露在紫外光（254 nm）下时，这些纳米结构的形态和孔隙率变化强烈影响其电学性质和紫外光检测。尽管我们使用了相同的生长技术，但对于在蓝宝石衬底上生长的高度多孔且结晶的纳米结构，却实现了最低的暗电流（0.14 nA）和最高的UV光敏性（182％）。通常，维持具有孔隙率的晶体结构是极其困难的。但是，在这里，我们通过结合孔隙率和结晶度这两个相反的事实，展示了一种设计可见盲光电探测器的有前途的方法，