An annealed intrinsic hydrogenated amorphous silicon germanium (i-a-SiGe:H) barrier layer deposited on a Si wafer ([111], 4 k Ω-cm) was employed to fabricate a planar interdigitated metal-semiconductor-metal photodetector (MSM-PD). At a bias of 15 V, and an incident light wavelength of 850 nm, this Si-based MSM-PD with an annealed 70 nm i-a-SiGe:H film had a responsivity of about 0.32 A/W, and a dark current density of around 400 fA/µ m2. Also, the temporal response of this device had a rise time of 21 ps, a fall-time of 236 ps and a full-width at half-maximum (FWHM) of 51 ps.

An hydrogenated amorphous silicon carbide (a-SiC:H) p-i-n thin-film light-emitting diode (TFLED), in which a composition-graded n layer and carbon-increasing p layer respectively replace the constant optical-gap p-a-SiC:H layer and n-a-SiC:H layer employed in the previously reported double graded-gap (DG) TFLED and which contains dopant-graded p-i and i-n junctions, was successfully fabricated to improve the electroluminescence (EL) of TFLED. This device had a brightness of 400 cd/m2 at an injection current density of 600 mA/cm2 and its EL threshold voltage (V th) was only 9.9 V. The device EL spectrum showed a peak at 586 nm wavelength and emitted yellowish-orange light. The proposed TFLED had good stability of EL intensity and the EL spectrum during normal operation. The optimum conditions of rapid thermal annealing (RTA), which improved the ohmic contact between the amorphous layer and external electrode of the device, were 5 min at 300°C in a 250 Torr H2 ambient.

n-i-p-n hydrogenated amorphous silicon (a-Si:H) layers were deposited onto porous silicon (PS) formed on p-type crystalline silicon (c-Si) by anodization and used to improve the current injection of a PS-based light-emitting diode (LED). The electroluminescence (EL) spectrum for the obtained PS-based LED with n-i-p-n a-Si:H layers showed the similar tendency as that of a photoluminescence (PL) signal for an as-anodized PS. The current conduction mechanisms of this PS-based LED were also studied.