Journal of the Korean Crystal Growth and Crystal Technology (한국결정성장학회지)

The Korea Association of Crystal Growth (한국결정성장학회)
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Thin film growth of ε-Ga2O3 and photo-electric properties of MSM UV photodetectors

ε-Ga2O3 박막 성장 및 MSM UV photodetector의 전기광학적 특성

  • Park, Sang Hun (Department of Materials Engineering, Korea Maritime and Ocean University) ;
  • Lee, Han Sol (Department of Materials Engineering, Korea Maritime and Ocean University) ;
  • Ahn, Hyung Soo (Department of Materials Engineering, Korea Maritime and Ocean University) ;
  • Yang, Min (Department of Materials Engineering, Korea Maritime and Ocean University)
  • 박상훈 (한국해양대학교 전자소재공학과) ;
  • 이한솔 (한국해양대학교 전자소재공학과) ;
  • 안형수 (한국해양대학교 전자소재공학과) ;
  • 양민 (한국해양대학교 전자소재공학과)
  • Received : 2019.06.24
  • Accepted : 2019.07.16
  • Published : 2019.08.31
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Abstract

In this study, we investigated the structural properties of $Ga_2O_3$ thin films and the photo-electrical properties of metal-semiconductor-metal (MSM) photodetectors deposited by Ti/Au electrodes. $Ga_2O_3$ thin films were grown at different temperatures using metal organic chemical vapor deposition (MOCVD). The crystal phase of $Ga_2O_3$ changed from ${\varepsilon}$-phase to ${\beta}$-phase depending on the growth temperature. The crystal structure of ${\varepsilon}-Ga_2O_3$ was confirmed by X-ray diffraction (XRD) analysis and the formation mechanism of crystal structure was discussed by scanning electron microscopy (SEM) images. From the results of current-voltage (I-V) and time-dependent photoresponse characteristics under the illumination of external lights, we confirmed that the MSM photodetector fabricated by ${\varepsilon}-Ga_2O_3$ showed much better photocurrent characteristics in the 266 nm UV range than in the visible range.

본 연구에서는 $Ga_2O_3$ 박막의 구조적 특성과 Ti/Au 전극을 증착하여 제작된 metal-semiconductor-metal (MSM) photodetector 소자의 광학적, 전기적 특성에 대해 연구하였다. 유기 금속 화학 증착법(metal organic chemical vapor deposition, MOCVD)을 이용해 서로 다른 온도에서 $Ga_2O_3$ 박막을 성장하였다. 성장온도에 따라 $Ga_2O_3$의 결정상이 ${\varepsilon}$-상에서 ${\beta}$-상으로 변화하는 것을 확인할 수 있었다. X-선 회절 분석(X-ray diffraction, XRD) 결과로 ${\varepsilon}-Ga_2O_3$의 결정구조를 확인하였고, 주사 전자 현미경(scanning electron microscopy, SEM) 이미지로 결정구조의 형성 메커니즘에 대해 논의하였다. 음극선 발광(Cathode luminescence, CL) 측정으로 $Ga_2O_3$의 발광성 천이에 관여하는 에너지 준위의 형성 원인에 대해 논의하였다. 제작된 MSM photodetector 소자의 외부 광에 대한 전류-전압 특성과 시간 의존성 on/off 광 응답 특성을 통해 ${\varepsilon}-Ga_2O_3$로 제작한 photodetector는 가시광보다 266 nm UV 파장 영역에서 훨씬 뛰어난 광전류 특성을 보이는 것을 확인하였다.

Keywords

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