Valentin Jmerik is a principal research scientist at the Ioffe Institute, where he received his Ph.D. and habilitation degrees in material science. Since 1996, he has worked in the MBE group of the Quantum-size Heterostructures Lab, studying the growth kinetics and strain engineering of III-Nitride-based heterostructures for optoelectronic and electronic devices. After an initial study of the plasma-assisted MBE of GaN and In-rich ternary nitrides, he embarked on R&D on the (Al,Ga)N material system, focusing on 2D GaN/AlN multilayer heterostructures, including multiple quantum wells and digital alloys, for their applications in deep UV optoelectronics.