Ultracompact Chip-Scale Refractometer Based on an InGaN-Based Monolithic Photonic Chip

Abstract

Optical refractometer constitutes the core element for many applications, from determining the purity and concentration of pharmaceutical ingredients to measuring the sugar content in food and beverages, and the analysis of petroleum. Here, we demonstrated the monolithic integration of light-emitting diodes (LEDs) and photodetectors (PDs) to fabricate ultracompact refractometers with a chip size of 475 × 320 μm2. The light emission and photodetection properties of the devices containing the same InGaN/GaN multi-quantum wells have been characterized, confirming that the PD can respond to the emission of the LED. The flip-chip assembly of the chip enables the exposed sapphire substrate to be in direct contact with the solution, and the refractive index sensing capability governed by the change of critical angle and Fresnel reflection at the sapphire/solution interface has been investigated. The processing of the optically smooth surface of sapphire and the integration of high-reflectance distributed Bragg reflector beneath the devices facilitate the amount of light received by the PD. The monolithic chip is capable of detecting solutions with a refractive index ranging from 1.3325 to 1.5148 RIU and exhibits a sensitivity of 7.77 μA/RIU and a resolution of 6.4 × 10–6 RIU at the LED current of 10 mA. Rapid real-time responses of 33.9 ms for rise time and 34.7 ms for fall time are obtained in the detected photocurrent, thereby verifying the feasibility of the chip-scale refractometer.

Progress on photovoltaic AlGaN photodiodes for solar-blind ultraviolet photodetection

“…Monolithic integration of DUV LEDs with photodetectors can facilitate achieving high-performance at the system level. The system-level enhancement originates from the integrated design and device ecosystem, which is also named "systems on a chip" [179][180][181][182][183][184] . For example, Wang et al designed a kind of integrated device composed of an AlGaN-based DUV LED and a multiplicative photoelectric converter (MPC), as shown in Fig . 15 [182] .…”

Micro Humidity Sensor Based on a GaN Chip With Silica Opal

“…1(b) and a distributed Bragg reflector (DBR) is used as a bottom mirror to promote upward luminescence. A detailed description of DBR can be found elsewhere [20]. After flip-chip bonding on a printed circuit board, the on-chip emitter and detector are connected with a current source and 0741-3106 © 2021 IEEE.…”

Микрооптопара (λ = 3.4 μm) на основе двойной гетероструктуры InAsSbP/InAs для измерения концентрации этанола в водном растворе методом МНПВО

“…В одном из вариантов такой интеграции на единой монокристаллической полупроводниковой подложке создают микрооптопару, состоящую из оптически связанных диодных источника и приемника излучения c характерными размерами активных областей от 20 до 300 µm [5][6][7][8]. Под оптической связью при этом подразумевается доставка в приемник излучения источника, вышедшего из полупроводника [5,6], либо доставка излучения, не покидающего монолитный чип, т. е. излучения, распространяющегося внутри прозрачной подложки [7][8][9]. В последнем случае монолитную микрооптопару светодиод (СД) -фотодиод (ФД) можно использовать как датчик многократного нарушенного полного внутреннего отражения (МНПВО), поскольку величина фототока в ФД зависит от показателя преломления и коэффициента поглощения вещества (аналита), имеющего оптический контакт с подложкой.…”