A great deal of interest has been focused on SSLSs, such as LEDs and lasers, and in particular, those that emit light in the blue and deep ultraviolet wavelengths. These devices may be capable of being incorporated into various applications, including solid-state lighting, biochemical disinfection and detection, high-density data storage, and the like.
Modern SSLSs, such as LEDs, typically include three major components: an electron supply layer (e.g., an n-type semiconductor layer), a hole supply layer (e.g., a p-type semiconductor layer), and a light generating structure formed between the electron supply layer and the hole supply layer. Generally, all types of SSLSs have an optimal range of operating currents within which they exhibit the highest efficiency and reliability. At low current densities, the efficiency of the SSLSs decreases due to an increased role of parasitic non-radiative recombination processes. When the current density is too high, the SSLSs exhibit efficiency droop caused by numerous processes such as temperature increases, electron leakage, poor hole injection, etc. For example, nitride-based SSLSs typically operate at high current density levels, and as a result, generally have a relatively high defect concentration. Maintaining the operating current within an optimal range is even more important for this device type. A typical range of current densities where nitride-based LEDs exhibit the highest efficiency at room temperature is generally within 50 A/cm2 to 300 A/cm2.
Attempts to control the operating current of SSLSs at a range that is considered between low current density levels and high density levels have relied on electronic circuits connected to the SSLSs to control the operating current. These electronic circuits are typically fabricated separately from the SSLSs and are connected to them using wiring or like techniques. These solutions may adversely affect the performance of the SSLSs by generating parasitic circuit parameters that increase switching time and lead to unwanted transients. In addition, the electronic circuits can have hybrid type connections to the SSLSs that can adversely affect system reliability and temperature stability.