Crystalline and band alignment properties of InAs/Ge (111) heterostructure

• Published in: Journal of alloys and compounds 2015-10, Vol.646, p.393-398
• Main Authors: Pal, Suparna, Singh, S.D., Dixit, V.K., Sharma, T.K., Kumar, R., Sinha, A.K., Sathe, V., Phase, D.M., Mukherjee, C., Ingale, Alka
• Format: Article
• Language: English
• Subjects: Ge-substrate; InAs; Photoelectron spectroscopy; Raman spectroscopy; X-ray diffraction
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2015.05.265

In the present work, important information on crystalline structure and band offset of InAs/Ge heterojunction epitaxially grown directly on Ge (111) substrate is presented. As revealed by high resolution x-ray diffraction (HRXRD) and Raman measurements the InAs nanostructures are highly crystalline and oriented with the substrate having predominantly zinc-blende (ZB) structure. The relaxation ratio of grown layer is of 95%. The lateral and vertical coherence lengths are estimated to be ∼65 nm and ∼14 nm, respectively, which closely match with atomic force microscopy results. As revealed from HRXRD experiments, two domains/sub-lattices of ZB InAs (111) structures having different stacking configurations were found to coexist. A band diagram is constructed for InO/InAs/Ge system. Valence band offset of 300 meV and conduction band offset of 20 meV for InAs/Ge have been determined. Hence, InAs/Ge (111) system can have potential application in low power devices. •InAs nanostructures on Ge(111) substrate were obtained using MOVPE.•Grown InAs is highly crystalline having predominantly zinc blende structure.•Coexistence of two domains of InAs with different stacking configurations is revealed.•Valence (conduction) band offsets of 300 (20) meV for InAs/Ge have been determined.•InAs/Ge heterojunction could have potential application in low power devices.