Carrier polarity modulation of molybdenum ditelluride (MoTe2) for phototransistor and switching photodiode applications

Aftab, Sikandar and Samiya, samiya and Rabia, Ms. and Yousuf, Saqlain and Khan, Muhammad Usman and Khawar, Rafia and Younus, Ayesha and Manzoor, Mumtaz and Iqbal, Muhammad Waqas and Iqbal, Muhammad Zahir (2020) Carrier polarity modulation of molybdenum ditelluride (MoTe2) for phototransistor and switching photodiode applications. Nanoscale, 12 (29). pp. 15687-15696. ISSN 2040-3364

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Abstract

Two-dimensional (2D) transition-metal dichalcogenides (TMDs) are layered
semiconductor materials that have been recently emerged as promising candidates for advanced
nano- and photoelectronic applications. Previously, various doping methods, such as surface
functionalization, chemical doping, substitutional doping, surface charge transfer, and
electrostatic doping, have been introduced, which are not stable or efficient. In this study, we
have developed carrier polarity modulation of molybdenum ditelluride (MoTe2) for
phototransistors and switching photodiodes. Initially, we treated p-MoTe2 in the N2
environment under DUV irradiation and found that the p-type MoTe2 changed to n-type
MoTe2. However, the treated devices exhibited environmental stability over a long period of
60 days. Kelvin probe force microscopy (KPFM) measurement demonstrated that the values
of work function for p-MoTe2 and n-MoTe2 were ~4.90 and ~4.49 eV, respectively, which
confirmed the carrier tunabilty. Also, first principal study was performed to confirm the n-type
carrier polarity variation. Interestingly, the n-type MoTe2 reversed its polarity to p-type after
the irradiation of the devices under DUV in an O2 environment. Additionally, a lateral
homojunction-based p-n diode of MoTe2 with a rectification ratio of ~2.5 × 104 was formed
with the value of contact potential difference of ~400 mV and estimated a fast rise time of 29
ms and decay time of 38 ms. Furthermore, a well self-biased photovoltaic behavior upon
illumination of light was attained and various photovoltaic parameters were examined. Also,
established VOC switching behavior at the p−n diode state by switching on and off the incident
light. We believe that this efficient and facile carrier polarity modulation technique may pave
the way for the development of phototransistors and switching photodiodes in advanced
nanotechnology.

Item Type:	Article
Subjects:	Q Science > QC Physics
Divisions:	Faculty of Engineering and Applied Sciences (FEAS) > Department of Basic Sciences Lahore
Depositing User:	Dr. Waqas Iqbal
Date Deposited:	26 Dec 2020 09:44
Last Modified:	31 Dec 2020 03:39
URI:	http://research.riphah.edu.pk/id/eprint/1174

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