In this study, we undertook detailed experiments to increase hydrogen production efficiency by optimizing the thickness of titanium dioxide (TiO2) thin films. TiO2 films were deposited on p-type silicon (Si) wafers using atomic layer deposition (ALD) technology. The main goal was to identify the optimal thickness of TiO2 film that would maximize hydrogen production efficiency while maintaining stable operating conditions. The photoelectrochemical (PEC) properties of the TiO2 films of different thicknesses were evaluated using open circuit potential (OCP) and linear sweep voltammetry (LSV) analysis. These techniques play a pivotal role in evaluating the electrochemical behavior and photoactivity of semiconductor materials in PEC systems. Our results showed photovoltage tended to improve with increasing thickness of TiO2 deposition. However, this improvement was observed to plateau and eventually decline when the thickness exceeded 1.5 nm, showing a correlation between charge transfer efficiency and tunneling. On the other hand, LSV analysis showed bare Si had the greatest efficiency, and that the deposition of TiO2 caused a positive change in the formation of photovoltage, but was not optimal. We show that oxide tunneling-capable TiO2 film thicknesses of 1~2 nm have the potential to improve the efficiency of PEC hydrogen production systems. This study not only reveals the complex relationship between film thickness and PEC performance, but also enabled greater efficiency and set a benchmark for future research aimed at developing sustainable hydrogen production technologies.

1. 서 론
2. 실험 방법
    2.1. 전극 제조
    2.2. 박막 증착
    2.3. 광전기화학 측정
3. 결과 및 고찰
    3.1. 에너지 레벨을 통한 전극 구조
    3.2. 광전기화학 분석
4. 결 론
Conflicts of Interest or Competing Interests
Acknowledgement
References
<저자소개>

• 김성규(단국대학교 에너지공학과) | Seong Gyu Kim (Department of Energy Engineering, Dankook University, Cheonan 31116, Republic of Korea)
• 조유진(단국대학교 에너지공학과) | Yu Jin Jo (Department of Energy Engineering, Dankook University, Cheonan 31116, Republic of Korea)
• 진선화(단국대학교 에너지공학과) | Sunhwa Jin (Department of Energy Engineering, Dankook University, Cheonan 31116, Republic of Korea)
• 서동혁(단국대학교 파운드리공학과) | Dong Hyeok Seo (Department of Foundry Engineering, Dankook University, Cheonan 31116, Republic of Korea)
• 김우병(단국대학교 에너지공학과, 단국대학교 파운드리공학과) | Woo-Byoung Kim (Department of Foundry Engineering, Dankook University, Cheonan 31116, Republic of Korea) Corresponding author