Abstract: A molecular single electron transistor (MSET) detector device (14) is described that comprises at least one organic molecule (87) connecting a drain electrode (84) and a source electrode (82). In use, said at least one organic molecule (87) provides a quantum confinement region. At least one analyte receptor site (90, 92) is provided in the vicinity of said at least one organic molecule (87) that bind molecules of interest (analytes). A fluid analyser (2) is also described that includes the MSET detector, a pre-concentrator (4) and a fluid gating structure (6). The fluid gating structure (6) is arranged to selectively route fluid from the pre-concentrator (4) to either one of the detector (14) and an exhaust port (12). The pre-concentrator (4), fluid gating structure (6) and detector (14) are each formed as substantially planar layers and arranged in a stack or cube.

Abstract: A quantum wire field-effect transistor having at least one, one-dimensional, elongate conducting means (14) provided by at least a first semiconductor layer surrounded by a wider bandgap, second semiconductor layer (12, 13) and extending between source (24) and drain (26) electrodes, and in which there is provided a backgate structure (8, 23) to control conduction in the elongate conducting means. The transistor can be a Single Electron Transistor (SET) wherein two adjacent gate electrode (16, 18) are disposed over the elongate conducting means to induce a quantum dot (17) therein, and it can be made with the first semiconductor layer material as GaAs and the second semiconductor layer material as AlGaAs. A method of making the transistor involves preferentially growing the elongate conducting means at the bottom of a groove (6) lined with second semiconductor layer (12).

Abstract: A single electron on hole field effect transistor fabricated from a narrow band gap semiconductor. The transistor is such that the valence and conduction bands have sufficiently similar energy levels such that a top region of the valence band at one point (37), e.g. under a gate electrode (34), within the current path of the transistor can be forced to be higher than the bottom region of the conduction band at another point within the transistor, allowing Zener tunelling to occur. The transistor is fabricated from semiconductors with band gaps narrow enough to allow this to occur, for instance InSb and InAISb, CdTe and CDxHg1−xTe.