Method of making semiconductor devices and techniques for controlled optical confinement

The disclosure is directed to improved techniques and devices employing an aluminum-bearing III-V semiconductor material and a native oxide of aluminum that is formed in the semiconductor material. Effective optical confinement, tailored to obtain desired operating conditions, can be achieved with a thick native oxide of aluminum that extends through at least one-third of the thickness of the aluminum-bearing layer in which the native oxide is formed. The resultant lateral index step can be made quite large and employed for devices such as ring lasers.