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Strathprints serves world leading Open Access research by the University of Strathclyde, including research by the Strathclyde Institute of Pharmacy and Biomedical Sciences (SIPBS), where research centres such as the Industrial Biotechnology Innovation Centre (IBioIC), the Cancer Research UK Formulation Unit, SeaBioTech and the Centre for Biophotonics are based.

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Membrane structures containing InGaN/GaN quantum wells, fabricated by wet etching of sacrificial silicon substrates

Park, S. and Liu, C. and Gu, E. and Dawson, M.D. and Watson, I.M. and Bejtka, K. and Edwards, P.R. and Martin, R.W. (2006) Membrane structures containing InGaN/GaN quantum wells, fabricated by wet etching of sacrificial silicon substrates. Physica Status Solidi C, 3 (6). pp. 1949-1952. ISSN 1862-6351

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Abstract

InGaN/GaN multiple quantum wells (MQWs) emitting at 410-505 nm, with either 3 or 16 repeat periods, were grown on commercial GaN-on-silicon templates using metal organic vapour phase epitaxy. Spectroscopic and structural studies confirmed these MQWs are of similar quality to analogues grown on sapphire substrates. Wet etching of the silicon (111) substrates in HF-based solutions allowed the MQW structures to be converted into membranes up to 2 mm in diameter, suspended above macroscopic via holes. Such a fabrication step is attractive for the production of microcavities, and other forms of surface emitting laser. Several MQWs have been compared by photoluminescence and cathodoluminescence spectroscopy before and after conversion to membranes. These measurements indicated a consistent increase in luminescence intensity after substrate removal, accompanied by small redshifts in peak position. We have further demonstrated plasma etching of membrane structures from the underside, as will be used to optimise structures for optical pumping, and used atomic force microscopy to monitor associated changes in surface roughness.