Distributed Feedback Lasers by Thermal Nanoimprint of Perovskites Using Gelatin Gratings

Abstract

To date, thermal nanoimprint lithography (NIL) for patterning hybrid perovskites has always involved an intricate etching step of a hard stamp material or its master. Here, we demonstrate for the first time the successful nanopatterning of a perovskite film by NIL with a lowcost polymeric stamp. The stamp consists of a dichromated gelatin grating structured by holographic lithography. The one-dimensional grating is imprinted into a perovskite film at 95 °C and 90 MPa for 10 min, resulting in a high quality second-order distributed feedback (DFB) laser. The laser exhibits an excellent performance with a threshold of 81 μJ/cm 2 , a line width of 0.32 nm, and a pronounced linear polarization. This novel approach enables cost-effective fabrication of high-quality DFB lasers compatible with different perovskite compositions and photonic nanostructures for a wide range of applications.

Multimode Lasing in All-Solution-Processed UV-Nanoimprinted Distributed Feedback MAPbI3 Perovskite Waveguides

“…The recorded DFB lasing threshold is comparable to other optically pumped second-order perovskite DFB lasers fabricated by various methods such as T-NIL, EBL, or via the deposition above a corrugated substrate (Table S2). We note that excitation source parameters must be accounted for as they significantly influence the reported threshold values . The longer pulses can impose thermal stress, increasing the amplification threshold.…”

“…We note that excitation source parameters must be accounted for as they significantly influence the reported threshold values. 17 The longer pulses can impose thermal stress, 46 increasing the amplification threshold.…”

“…In another approach, by virtue of their soft nature, perovskite films can be directly patterned by thermal nanoimprint lithography (T-NIL) , under high pressure at elevated temperatures. In particular, T-NIL combines direct surface texturing with thermal recrystallization, which modifies the perovskite morphology and grain size. , However, the use of high imprint pressures (up to 900 bar) and thermal heating cycles cause stamp wear that reduces the imprint quality, whereas long T-NIL cycle times (up to 40 min) , limit the attainable throughput.…”

“…In particular, T-NIL combines direct surface texturing with thermal recrystallization, which modifies the perovskite morphology and grain size. 14,16 However, the use of high imprint pressures (up to 900 bar) 17 and thermal heating cycles cause stamp wear that reduces the imprint quality, whereas long T-NIL cycle times (up to 40 min) 12,18 limit the attainable throughput.…”

Laser patterning of large-scale perovskite single-crystal-based arrays for single-mode laser displays

“…The crystallinity of thin films is another essential factor for the top-down fabrication of high-performance microlaser arrays. Most perovskite microlasers reported to date, such as the vertical-cavity laser [26,27] and distributed feedback laser [28,29], have been fabricated on only polycrystalline perovskite thin films. Generally, higher trap states are produced by high-density grain boundaries in polycrystalline films, which impacts the charge-carrier lifetimes and causes nonradiative recombination processes that limit the device performance [30,31].…”