Search query: GaN based UV  photodetector having asymmetric electrodes

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abstract: The present research demonstrates the fabrication and comparative performance of GaN based metal semiconductor metal (MSM) ultraviolet (UV) photodetector on sapphire substrate. The MSM device has been fabricated with gold (Au) in an inter digitized electrode (IDE) form with different geometry on molecular beam epitaxially (MBE) grown GaN. The current voltage characteristics shows the minimum dark current of 68 nA and 40 nA and photocurrent of 24.5 \mu$A and 9.02 \mu$A for rectangular asymmetric (RA) and circular asymmetric (CA) geometry respectively. The room temperature characterization was performed under the illumination of 365 nm light at the applied voltage of 5V. The responsivity and efficiency enhanced by almost three times by circular geometry due to the reduced two dimensional and three dimensional electric field distribution effects in CA IDE.
author_names: Indu Kumari

Santu Nandi

Ankush Bag
title: Performance Evaluation of GaN based Selective UV Photodetector by Varying Metal Semiconductor Metal Geometry
venue: 2019 Electron Devices Technology and Manufacturing Conference (EDTM)
year: 2019

abstract: Optoelectronic properties of nonpolar a plane GaN are superior along the [0002] azimuth direction compared to other azimuth directions. We have grown a GaN on r sapphire, and interdigitated electro.
author_names: Rohit Pant

Deependra Kumar Singh

Arun Malla Chowdhury

Basanta Roul

Karuna Kar Nanda

Saluru Baba Krupanidhi
title: Highly Responsive, Self Powered a GaN Based UV A Photodetectors Driven by Unintentional Asymmetrical Electrodes
year: 2020

abstract: Abstract This study demonstrates a novel, simple, and process compatible approach to fabricate UV photodetectors (PDs) based on an asymmetric metal semiconductor metal (MSM) structure, with ZnO nanoflowers (NFs) as the active layer. A network of silver nanowires (AgNWs) is used as a low resistivity transparent electrode. The MSM UV PDs based on AgNWs/ZnONFs/AgNWs showed low dark current of the order of nA and a photo to dark current ratio of two orders of magnitude at 3 V and more than 3 orders of magnitude at 3 V of asymmetric MSM UV PDs based on AgNWs/ZnONFs/AgNWs with a source (S) and drain (D) channel width of 570 mm. The UV sensitivity and responsivity at 0 V of the device with the wider S/D channel was as high as 6.34 x 104 and 9.4 x 10 3 AW 1, respectively. The findings suggest that UV PDs based on ZnONFs with asymmetric Ag network electrodes with ZnONFs hold promise for use in future optoelectronic devices.
author_names: Manoj Kumar

Hakyung Jeong

Dongjin Lee
title: UV photodetector with ZnO nanoflowers as an active layer and a network of Ag nanowires as transparent electrodes
venue: Superlattices and Microstructures
year: 2019

abstract: Abstract A scheme illustrating electrode engineering in metal semiconductor metal geometry is employed for fabricating GaN based high performance ultraviolet photodetectors. The effect of different metal semiconductor (Au, Ti/Al and Al) junctions on photon assisted charge carrier transport and the current conduction is explored. Depending upon work function of the metals, barrier height varies which contributed towards different characteristics of the device revealing linear and non linear behaviour of the electrical measurements from the non rectifying and rectifying contact at the metal semiconductor interface respectively. A maximum photoresponsivity efficiency of 280.4 mA/W and 107.04% respectively, under 5 V applied bias in the visible blind region was measured from the device with rectifying Au electrodes. While, the photoresponsivity values of 219 mA/W and 200 mA/W under the same bias has been achieved from devices measured with near Ohmic contacts using Ti/Al and Al electrodes, respectively. The enhancement in detector's performance with Au electrode has been attributed to the built in electric field as well as the presence of internal gain which can promote efficient transport of charge carriers through the metal semiconductor interface. Thus, an approach has been adopted to enhance the photoresponsivity of the fabricated GaN based optoelectronic devices which could be utilized for wide range of industrial, military, environmental and biological applications.
author_names: Neha Aggarwal

Shibin Krishna

Shubhendra Kumar Jain

Arzoo Arora

Lalit N Goswami

Alka Jyoti Sharma

Sudhir Husale

A Gundimeda

Govind Gupta
title: Impact on photon assisted charge carrier transport by engineering electrodes of GaN based UV photodetectors
venue: Journal of Alloys and Compounds
year: 2019

abstract: Abstract In this work, we have investigated the potential of Pt nanoparticles in modification the surface of b Ga2O3 layer, which improved the performance of b Ga2O3 based device with a novel asymmetric metal semiconductor metal (MSM) structure. The results shown that the disadvantage of high dark current in traditional MSM detector can be overcome by the novel asymmetric MSM detector and the Pt nanoparticles can remarkably enhance the generation of photogenerated carriers via formation of the local surface plasmon resonance effect. As a result, the obtained device has a high responsivity of 29.08 A/W, an excellent detectivity (D* of 2.16x1011 Jones and a high normalized photocurrent to dark current ratio (NPDR) of 5.156x106 mW 1cm2, exhibiting an increase by 88.5% 677% and 3024.8% compared to pristine device. At last, the energy band theory and the finite difference time domain (FDTD) calculation were used to explain the mechanism of device performance improvement. These results of our study provide an effective method for fabricating high performance solar blind photodetector and pave the way for the potential application of Pt nanoparticles in the field of deep UV photodetector.
author_names: Jian Lou

Zhuo Wang

Siwei Ji

Jiajie Chen

Yanfei Hu

Lei Yuan

Yuming Zhang

Renxu Jia
title: Surface modification of b Ga2O3 layer using pt nanoparticles for improved deep UV photodetector performance
year: 2021

abstract: Fabrication of very thin GaN ultraviolet photodetectors on Si (111) substrate integrated with asymmetric (Pt Ag, Pt Cr) metal semiconductor metal (MSM) structure have been illustrated. Designed GaN photodetection device displays significant enhancement in responsivity for asymmetric (Pt Ag) MSM structure (280 mA/W) in comparison to symmetric (Pt Pt) MSM structure (126 mA/W) at 10 V bias. The fabricated asymmetric and symmetric devices also exhibit fast response time in the range of 30 59 ms. The enhancement in responsivity using asymmetric MSM structure ascribed to large difference in work function which lead to change in Schottky barrier height of the metal semiconductor junction. Additionally, power dependent photoresponse analysis of GaN asymmetric (Pt Ag) ultraviolet photodetector was showing a responsivity of 116 mA/W at low optical power of 1 mW. Such GaN asymmetric MSM ultraviolet photodetectors having high responsivity can extensively be used for low power, high speed ultraviolet photo detection applications.
author_names: Shubhendra Kumar Jain

Neha Aggarwal

Shibin Krishna

Rahul Kumar

Sudhir Husale

Vinay Gupta

Govind Gupta
title: GaN UV photodetector integrated with asymmetric metal semiconductor metal structure for enhanced responsivity
venue: Journal of Materials Science: Materials in Electronics
year: 2018

abstract: Near ultraviolet (NUV) light emitting diodes (LEDs) have been used in several potential applications such as UV curing and biochemical sensors. However, the internal quantum efficiency (IQE) of NUV LEDs is still a crucial issue. To improve the IQE, in this paper, an asymmetric triangular multiple quantum well (MQW) structure was used, which exhibited a higher emission efficiency and lower efficiency droop with nitrogen face oriented inclination. This is in contrast to the trend observed in blue LEDs. Furthermore, we demonstrated that holes are more confined in MQWs with nitrogen face oriented inclination than in MQWs with gallium face oriented inclination. Moreover, simulations revealed that the IQE improved by approximately 32% compared with that of symmetric square MQW NUV LEDs; this trend was also confirmed through experimental results. The external quantum efficiency of thin film flip chip LEDs with nitrogen face oriented inclination MQWs was 52%
author_names: Heng Li

Chia Jui Chang

Shiou-Yi Kuo

Haocheng Wu

Huamao Huang

Tien-Chang Lu
title: Improved Performance of Near UV GaN Based Light Emitting Diodes With Asymmetric Triangular Multiple Quantum Wells
venue: IEEE Journal of Quantum Electronics
year: 2019

abstract: Self powered photodetectors have demonstrated potential for developing future wireless and implantable devices. Herein, we present a self powered UV photodetector with an ultrahigh photoresponse based on vertically oriented and high crystalline quality n type GaN nanorod arrays: poly(methyl methacrylate)/p Si heterojunction. Benefiting from the highly efficient separation and transport of photoexcited electron hole pairs, significant improvements in photoresponsivity are experimentally obtained. In a zero biased self powered detection mode, a 6.7AW 1 responsivity and 2.68x1013 Jones detectivity are achieved under 355 nm light illumination, and the response time is as low as 0.29/3.07 ms (rise/fall times)
author_names: Yulin Zheng

Xin Tang

Yuhui Yang

Wenliang Wang

Guoqiang Li
title: Vertically aligned GaN nanorod arrays/p Si heterojunction self powered UV photodetector with ultrahigh photoresponsivity.
venue: Optics letters
year: 2020

abstract: A simplistic design of a self powered UV photodetector device based on hybrid reduced graphene oxide (r GO)/gallium nitride (GaN) is demonstrated. Under zero bias, the fabricated hybrid photodetector shows a photosensivity of ~85% while the ohmic contact GaN photodetector with an identical device structure exhibits only ~5.3% photosensivity at 350 nm illumination (18 mW/cm2) The responsivity and detectivity of the hybrid device were found to be 1.54 mA/W and 1.45 x 1010 Jones (cm Hz 1/2 W 1) respectively, at zero bias with fast response (60 ms) recovery time (267 ms) and excellent repeatability. Power density dependent responsivity and detectivity revealed ultrasensitive behaviour under low light conditions. The source of the observed self powered effect in the hybrid photodetector is attributed to the depletion region formed at the r GO and GaN quasi ohmic interface.
author_names: N Guru Prakash

Manjri Singh

Gaurav Kumar

Arun Barvat

Kritika Anand

Prabir Pal

Surinder P Singh

Suraj P Khanna
title: Ultrasensitive self powered large area planar GaN UV photodetector using reduced graphene oxide electrodes
year: 2016

abstract: Hybrid systems based on the combination of crystalline bulk semiconductors with 2D crystals are identified as promising heterogeneous structures for new optoelectronic applications. The direct integration of III V semiconductors on 2D materials is very attractive to make practical devices but the preservation of the intrinsic properties of the underlying 2D materials remains a challenge. In this work, we study the direct epitaxy of self organized GaN crystals on graphene. We demonstrate that severe metal organic chemical vapor deposition growth conditions of GaN (chemically aggressive precursors and high temperatures) are not detrimental to the structural quality and the charge carrier mobility of the graphene base plane. Graphene can therefore be used both as an efficient sensitive material and as a substrate for GaN epitaxy to make a self assembled UV photodetector. A responsivity as high as 2 A W 1 is measured in the UV A range without any further postprocessing compared to simple deposition of contact electrodes. Our study opens the way to build new self assembled 2D/III V hybrid optoelectronic devices by direct epitaxy.
author_names: Timotee Journot

Vincent Bouchiat

B Gayral

Jean Dijon

Berangere Hyot
title: Self Assembled UV Photodetector Made by Direct Epitaxial GaN Growth on Graphene.
venue: ACS applied materials interfaces
year: 2018