Low temperature carrier transport mechanism and photo-conductivity of WSe2

JOURNAL OF ALLOYS AND COMPOUNDS

卷:869

Article

Kaur, Manjot¹  Singh, Kulwinder¹  Chauhan, Ishant¹  Singh, Hardilraj¹  Sharma, Ram K.²  Vij, Ankush³  Thakur, Anup⁴  Kumar, Akshay¹ 

[1] Sri Guru Granth Sahib World Univ, Dept Nanotechnol, Adv Funct Mat Lab, Fatehgarh Sahib 140406, Punjab, India

[2] Univ Petr & Energy Studies UPES, Ctr Interdisciplinary Res, Dehra Dun 248007, Uttarakhand, India

[3] Univ Petr & Energy Studies UPES, Dept Phys, Dehra Dun 248007, Uttarakhand, India

[4] Punjabi Univ, Dept Basic & Appl Sci, Patiala 140002, Punjab, India

关键词: WSe2;    Trap states;    Hopping conduction;    Photodetector;   

DOI  :  10.1016/j.jallcom.2021.159369

来源: Elsevier

【 摘 要 】

This work reports the electrical-transport and temperature-dependent photoconductivity in tungsten diselenide (WSe2) thin films. Temperature-dependent electrical conductivity has been demonstrated using different models. At lower temperatures (< 190 K), carriers become localized to small regions in the film due to Mott's hopping mechanism. The middle-temperature region (190-273 K) follows Seto's parameters and obtained low barrier height (0.0873 eV) may be responsible for the improved carrier mobility. At higher temperature (> 273 K) region, thermally activated conduction is dominated with two activation energies of similar to 138 meV and 98 meV. The peaks obtained in photoluminescent analysis attributes to the presence of midbandgap states or defect states which play an important role in the photoconductivity of WSe2. The transient photoconductivity measurements show consistent temperature-dependent behaviour. The effect of light intensity and wavelength variation on the photoconductivity of WSe2 thin films is also discussed. The photo-current is 1.19 * 10(-5) A at 125 K, while at 350 K was observed to be 3.12 * 10(-4) A. The light-on/off current cycles show that the current can recover to its initial state after various cycles, which points to the WSe2 thin-film device's stable and reversible properties that can be used in optoelectronic applications. (C) 2021 Elsevier B.V. All rights reserved.

【 授权许可】

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