Radiation hard UV detectors against terrorist threats

Project title: Radiation hard UV detectors against terrorist threats ( G-5453  ) 
Project Co-Directors:

Prof. Leonid Chernyak, University of Central Florida, Orlando, FL, USA (NPD)
Prof. Igor Lubomirsky, Weizmann Institute of Science, Rehovot, Israel (PPD)

Kickoff Date : June 1, 2018
Duration: 42 month
NATO Budget: 360,000 EUR

The main objectives of this NATO collaborative project are as follows:

•           To investigate the influence of gamma (proton, ion, alpha) irradiation on the minority carrier transport in wide bandgap semiconductors: minority carrier diffusion length and lifetime.

•           To identify and study the radiation-induced defects and their impact on fundamental material’s properties on the one hand, and device functionality on the other.

•           To characterize the effects of irradiation on the figures of merit (spectral and temporal photoresponse and noise) of photodetector device structures and to determine solid-state forward-bias electron injection regimes leading to improved functionality.

•           To study the mechanism and impact of annealing on the above-mentioned properties.

Summary of Accomplishments

While working on the project since its kick-off, an emerging Ga2O3 ultra-wide bandgap semiconductor as well as GaN, were thoroughly investigated under electron beam irradiation and alpha-particles irradiation. It has been found that electron irradiation results in up to several-fold increase of minority carrier diffusion length in these semiconductors. Consistent changes were observed in the material’s optical properties. Additionally, the levels involved in the electron irradiation-induced effects were identified.

Publications

  1. S. Modak, J. Lee, L. Chernyak, J. Yang, F. Ren, S. J. Pearton, S. Khodorov and                            I. Lubomirsky, "Electron injection-induced effects in Si-doped β-Ga2O3", AIP Adv., 9, 1, 015127 (2019).DOI: 10.1063/1.5079730 
  2. S. Modak, L. Chernyak, S. Khodorov, I. Lubomirsky, J. Yang, F. Ren and S. J. Pearton, "Impact of Electron Injection and Temperature on Minority Carrier Transport in Alpha-Irradiated β-Ga2O3 Schottky Rectifiers", ECS Journal of Solid-State Science and Technology, 8, 7, Q3050-Q3053 (2019).    DOI: 10.1149/2.0101907jss  
  3. Sushrut Modak, Leonid Chernyak, Igor Lubomirsky, Sergey Khodorov, “Continuous and time-resolved cathodoluminescence studies of electron injection induced effects in gallium nitride”. in Advanced Technologies for Security Applications - NATO Science for Peace and Security Cluster Workshop on Advanced Technologies, 17-18 September 2019, Leuven, Belgium. pp. 109-117. DOI 10.1007/978-94-024-2021-0_11  
  4. Sushrut Modak, Leonid Chernyak, Sergey Khodorov, Igor Lubomirsky, Arie Ruzin, Minghan Xian, Fan Ren, Stephen J. Pearton (2020)    “Effect of Electron Injection on Minority Carrier Transport in 10 MeV Proton Irradiated β-Ga2O3 Schottky Rectifiers”, ECS Journal of Solid-State Science and Technology, vol. 9, article 045018.   DOI: 10.1149/2162-8777/ab902b 
  5. Sushrut Modak, Leonid Chernyak, Minghan Xian, Fan Ren, Stephen Pearton, Sergey Khodorov, Igor Lubomirsky, Arie Ruzin, and Zinovi Dashevsky (2020) “Impact of Electron Injection on Carrier Transport and Recombination in Unintentionally Doped GaN”, J. Appl. Phys., 128, article 085702.    DOI: 10.1063/5.0017742

Conference presentations

Leonid Chernyak, “Electron Injection-Induced Effects in Wide and Ultra-Wide Bandgap Semiconductors: Physics and Applications”, Physics Department, University of Padova, Italy.                    October 4, 2018.

Leonid Chernyak, “Electron Injection Effects in Ga2O3 and other wide bandgap semiconductors”, Hungarian Academy of Science, Budapest, April 17, 2019.

Igor Lubomirsky, “Radiation hard UV-detectors against terrorist threats”, NATO workshop, Leuven, Belgium, October 2019.

Sushrut Modak, Leonid Chernyak, Minghan Xian, Fan Ren, Stephen Pearton, Sergey Khodorov, Igor Lubomirsky, Zinovi Dashevsky, “Effect of Electron Injection on Minority Carrier Transport Properties in Unintentionally Doped GaN”, Pacific Rim Meeting on Electrochemical and Solid-State Science, October 4-9, 2020.

The problem: 

     

  The detector performance degrades because carrier recombine via traps in the band gap. 

   

 The detector performance degrades because carrier recombine via traps in the band gap. Filling the gap by applying short bursts of forward bias fills up the traps!        

 

Electron injection in GaN by forward bias results in large and long lasting increase of L and corresponding enhancement of quantum efficiency.

    

1 – Spectral response before Gamma Irradiation;

2 – Response after 1000 Gy dose (»30 minutes of in near earth orbit);

3 – Response after 3 C/cm2 (60 sec, 50 mA/cm2) injection following Gamma-Irradiation.