Fabrication of micro-light-emitting diodes in nanoimprint lithography with diamond molds

以聚甲基丙烯酸甲酯（PMMA）为压印材料，采用化学气相沉积（CVD）金刚石模具，利用纳米压印技术制备了微型有机发光二极管（OLED）。在电子束光刻技术中，采用Bi_4Ti_3O_（octylate）（oxide）掩模，用NIL工艺制备了金刚石模具<l2>。开发了使用直流（DC）无芯电动机的驱动功率的紧凑压印装置（宽28 cm，长15 cm，高25 cm）。实验结果表明，最佳压印工艺条件为：压印压力0.8MPa，压印时间15 mm，基片温度180℃，剥离温度70℃。制备了间距为30 μm和40 μm的凹方形点CVD金刚石模具。8-羟基喹啉-铝（Alq）、聚（9-乙烯基咔唑）（PVK）和香豆素-6分别用作电子传输、空穴传输和发射掺杂剂材料。采用压印技术制备的30 μm正方形点阵OLED器件结构为ITO PVK（100 nm）/Alq（50 nm）/Al（100 nm）。我们展示了微型OLED器件的成功制造和操作。

Fabrication of micro-organic light emitting diodes (OLED) in nanoimprint lithography (NIL) with chemical vapor deposited (CVD) diamond molds using polymethyl methacrylate (PMMA) as an imprinting material was investigated. The diamond molds using NIL process were fabricated with Bi_4Ti_3O_<l2> octylate (oxide) mask in electron beam lithography technology. The compact imprint apparatus (28 cm in width, 15 cm in length and 25 cm in height) using the driving power of a direct current (DC) coreless motor was developed. It was found that the optimum imprint conditions are the following: imprinting pressure, press time, substrate temperature and removal temperature were 0.8 MPa 15 mm, 180℃ and 70℃ respectively. The resulting CVD diamond molds of a concave square dot with 30 μm and 40 μm pitch were fabricated. 8-Hydroxyquinoline-aluminum (Alq), Poly(9-vinylcalbazole) (PVK) and Coumarin-6 are used as electron transport, hole transport and an emitting dopant material, respectively. The device structure of 30 μm square dot OLED fabricated by imprinting technique is indium tin oxide (ITO)PVK(lOOnm)/Alq(5Onm)/Al(lOOnm). We demonstrated successful fabrication and operation of micro-OLED devices.