| Citation | Distinguished for his contributions to elucidating the electronic properties of semiconductors, particularly low dimensional structures, through the use of magnetotransport, hydrostatic pressure and spectroscopic techniques. Of particular note in his earlier work was the use of magnetophonon resonance to identify the phonon-assisted intervalley scattering mechanisms for condution electrons in n-type Si, and magneto-photoluminescence to identify Cr-related axial complexes in GaAs and GaP. He has shown that the DX level in a GaAs arises from simple substitutional donars, not complexes as previously thought. His recent work on low dimensional structures has revealed the importance of space charge effects and has led to the development of an asymmetric resonant tunnelling device which exhibits intrinsic bistability in its current-voltage characteristics. He has made important contributions to the coherent versus sequential tunnelling contraversy in double resonant tunnelling devices, his work clearly demonstrating the importance of the sequential process. He has observed novel effects arising from tunnelling into hybrid magneto-electric quantised states in low dimensional structures which give rise to edge currents in the Quantum Hall Effect regime. |