Formation of van der Waals Stacked p-n Homojunction Optoelectronic Device of Multilayered ReSe2 by Cr Doping

The formation of p- or n-type material via impurity doping should be crucial and essentially prior to the establishment of junction devices in semiconductor processing. Especially in a 2D transition-metal dichalcogenide (TMD), dopant selection for growing p- and n-type TMD semiconductors may suffer much higher difficulty and complexity than conventional Si and III-V compounds owing to the complicated valences occurred in transition metals. Different amount of chromium doped in ReSe2 interestingly showing dissimilar carrier types of p-ReSe2 with Cr 10% and 20% doping and n-ReSe2 with Cr 0%, 1%, and 5% doping, respectively, is presented here. According to structural and optical characterization, the crystal structure and bandgap of the Cr-doped ReSe2 remain unchanged in which a deeper donor of Cr6+ can exist in n-ReSe2 (1% and 5%) while a shallow acceptor of Cr3+ may appear in p-ReSe2 multilayer (10% and 20%). A p-n homojunction light-emitting diode made by stacking multilayered n-ReSe2 (Cr 0%) and p-ReSe2 (Cr 20%) is first fabricated, and it emits an electroluminescence of approximate to 946 nm from the band edge. Another p-n homojunction solar cell is also manufactured to exhibit a maximum axial conversion efficiency of eta approximate to 1.05% along with the b-axis polarization of ReSe2.

Automated summary

This study focuses on impurity doping experiments in 2D transition-metal dichalcogenides (TMD). Different carrier types were observed under different chromium doping concentrations. Structural and optical characterization revealed that the crystal structure and bandgap of chromium-doped ReSe2 remained unchanged.