Abstract
A novel technique is proposed for the simultaneous extraction of energy distribution of donor- and acceptor-like interface trap states [<inline-formula> <tex-math notation="LaTeX">{D}_{\text {it}\_{}{D}} </tex-math></inline-formula>(<inline-formula> <tex-math notation="LaTeX">{E} </tex-math></inline-formula>) and <inline-formula> <tex-math notation="LaTeX">{D}_{\text {it}\_{}{A}} </tex-math></inline-formula> (<inline-formula> <tex-math notation="LaTeX">{E} </tex-math></inline-formula>)] over a wide range of bandgap energy using deep UV light with sub-bandgap (<inline-formula> <tex-math notation="LaTeX">{E}_{\text {ph}}={h}\nu < {E}_{g} </tex-math></inline-formula>) photons less than the bandgap of the <inline-formula> <tex-math notation="LaTeX">\beta </tex-math></inline-formula>-gallium oxide (<inline-formula> <tex-math notation="LaTeX">\beta </tex-math></inline-formula>-Ga 2 O 3 ) channel material in the <inline-formula> <tex-math notation="LaTeX">\beta </tex-math></inline-formula>-Ga 2 O 3 field-effect transistors. In the proposed technique, we characterized <inline-formula> <tex-math notation="LaTeX">{D}_{\text {it}\_{}{D}} </tex-math></inline-formula>(<inline-formula> <tex-math notation="LaTeX">{E} </tex-math></inline-formula>) and <inline-formula> <tex-math notation="LaTeX">{D}_{\text {it}\_{}{A}} </tex-math></inline-formula>(<inline-formula> <tex-math notation="LaTeX">{E} </tex-math></inline-formula>) separately based on the difference in the gate voltage (<inline-formula> <tex-math notation="LaTeX">{V} _{\text {GS}} </tex-math></inline-formula>)-dependent ideality factors [<inline-formula> <tex-math notation="LaTeX">{d} \Delta \eta </tex-math></inline-formula>(<inline-formula> <tex-math notation="LaTeX">{V} _{\text {GS}} </tex-math></inline-formula>)/<inline-formula> <tex-math notation="LaTeX">dV_{\text {GS}} </tex-math></inline-formula>] for the photoresponsive carriers excited from <inline-formula> <tex-math notation="LaTeX">{D} _{\text {it}\_{}{D}} </tex-math></inline-formula>(E) and <inline-formula> <tex-math notation="LaTeX">{D} _{\text {it}\_{}{A}} </tex-math></inline-formula>(<inline-formula> <tex-math notation="LaTeX">{E} </tex-math></inline-formula>) under two different regions (<inline-formula> <tex-math notation="LaTeX">{V} _{\text {ON}}< {V}_{\text {GS}}< {V}_{\text {FB}} </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">{V} _{\text {FB}}< {V}_{\text {GS}}< {V}_{T} </tex-math></inline-formula>) in the subthreshold operation.