Shell Thickness-Dependent Tunable Threshold Voltage Single Quantum Dot Rectification Diode

Kenath, Gopal Sankar and Mahadevu, Rekha and Sharma, Anand and Gangwar, Vinod K. and Chaterjee, Sandip and Pandey, Anshu and Pal, Bhola N (2018) Shell Thickness-Dependent Tunable Threshold Voltage Single Quantum Dot Rectification Diode. In: JOURNAL OF PHYSICAL CHEMISTRY C, 122 (5). pp. 3176-3181.

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Abstract

Ambient atmosphere single colloidal quantum dot (QD) rectifying diode with tunable threshold voltage has been fabricated by using a type-II heterojunction core/shell structure with a device geometry ITO/ZnO/QDs. Specifically, in our work we have used ZnTe/CdS core/shell QDs in which hole wave function strongly confined to the core, whereas the lowest-lying conduction band state resides in the shell. Current voltage (I-V) characterization of this device has been done using an ambient atmosphere scanning tunneling microscope. The scanning tunneling spectra (STS) shows high rectification with a ratio of 10(3). The rectification is found to arise because of the bias-dependent band alignment of ZnO/QDs heterojunction and the effect of shell of each QD that presents a barrier for hole tunneling into the substrate. This barrier is overcome by the externally applied bias. This mechanism is distinct from the rectification observed in conventional p-n junction diodes. In particular, we find that even for QDs with optical band gaps of eV, the threshold voltage may be tuned from similar to 1 to 3 V by regulating shell thickness.

Item Type:	Journal Article
Publication:	JOURNAL OF PHYSICAL CHEMISTRY C
Publisher:	AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA
Additional Information:	Copy right for the article belong to AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	08 Mar 2018 19:08
Last Modified:	08 Mar 2018 19:08
URI:	http://eprints.iisc.ac.in/id/eprint/59123

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