Experimental evidences of quantum confined 2D indirect excitons in single barrier GaAs/AlAs/GaAs heterostructure using photocapacitance at room temperature

Autor(es)

Bhunia, Amit ^{[1, 2]} ; Singh, Mohit Kumar ^{[1, 2]} ; Galvao Gobato, Y. ^[3] ; Henini, Mohamed ^{[4, 5]} ; Datta, Shouvik ^{[1, 2]}

Afiliação do(s) autor(es)

^[1] Indian Inst Sci Educ & Res, Dept Phys, Pune 411008, Maharashtra - India

^[2] Indian Inst Sci Educ & Res, Ctr Energy Sci, Pune 411008, Maharashtra - India

^[3] Univ Fed Sao Carlos, Dept Fis, BR-13560905 Sao Carlos, SP - Brazil

^[4] Univ Nottingham, Sch Phys & Astron, Nottingham NG7 2RD - England

^[5] Univ South Africa UNISA, Coll Grad Studies, Nanosci & Nanotechnol Labs, POB 392, Pretoria - South Africa

• Tipo de documento: Artigo Científico
• Fonte: Journal of Applied Physics; v. 123, n. 4 JAN 28 2018.
• Citações Web of Science: 1

Resumo

We investigated excitonic absorptions in a GaAs/AlAs/GaAs single barrier heterostructure using both photocapacitance and photocurrent spectroscopies at room temperature. Photocapacitance spectra show well defined resonance peaks of indirect excitons formed around the Gamma-AlAs barrier. Unlike DC-photocurrent spectra, frequency dependent photocapacitance spectra interestingly red shift, sharpen up, and then decrease with increasing tunneling at higher biases. Such dissimilarities clearly point out that different exciton dynamics govern these two spectral measurements. We also argue why such quantum confined dipoles of indirect excitons can have thermodynamically finite probabilities to survive even at room temperature. Finally, our observations demonstrate that the photocapacitance technique, which was seldom used to detect excitons in the past, is useful for selective detection and experimental tuning of relatively small numbers (similar to 10(11)/cm(2)) of photo-generated indirect excitons having large effective dipole moments in this type of quasi-two dimensional heterostructures. Published by AIP Publishing. (AU)

• Processo FAPESP: 16/10668-7 - Propriedades óticas, magneto-óticas, de transporte e magneto-transporte de materiais semicondutores bidimensionais baseados em materiais de transição dicalcogenados
• Beneficiário: Yara Galvão Gobato
• Modalidade de apoio: Auxílio à Pesquisa - Regular