| In this thesis research based on the quantum confinement of electrons in three dimensions, a spectrally resolving quantum dot photodetector has been designed and fabricated which is able to discriminate wavelengths in the visible region. To realize this, a monolayer of CdSe nanoparticles with 5.4nm diameter has been sandwiched between two organic layers of Hexanedithiol, all on a highly p-doped InP substrate. To make the top contact, a thin semitransparent layer of gold deposited on the top of the device. The two layers of Hexanedithiol act as tunnel barriers for electrons inside the nanoparticles. It is predicted that by changing the bias voltage across the device, the specific energy states inside the nanocrystal should align with the conduction band edge of the InP. Any excited carriers in these energy levels will tunnel trough the organic barrier and be collected as the photocurrent. By changing the wavelength of the incident light, the device shows increase in the current at certain voltages. Comparing which peaks in different wavelengths are present, shows that the device has a spectrally dependent response to the incident light. |
