A light emitting device comprises a body of an indirect bandgap semiconductor material. A junction region is formed between a first region in the body of a first doping kind and a second region of the body of a second doping kind of first concentration. A third region of the second doping kind of a second concentration is spaced from the junction region by the second region. The second concentration is higher than the first concentration. A terminal arrangement is connected to the body for, in use, reverse biasing the first junction region into a breakdown mode, thereby to cause emission of light. The device is configured such that a depletion region associated with the junction region reaches through the shaped region to reach the third region, before the junction enters the breakdown mode.